Ok, let's start off with an extended quote from When Victims Become Killers (pp 64-65) by Mahmood Mamdani that contextualizes that quote.

THE RACIALIZATION OF THE TUTSI/HUTU DIFFERENCE

The racialization of the Tutsi/Hutu was not simply an intellectual construct, one which later and more enlightened generations of intellectuals could deconstruct and discard at will. More to the point, racialization was also an institutional construct. Racial ideology was embedded in institutions, which in turn undergirded racial privilege and reproduced racial ideology. It is this political-institutional fact that intellectuals alone would not be able to alter. Rather, it would take a political-social movement to be dismantled.

As a process both ideological and institutional, the racialization of the Tutsi was the creation of a joint enterprise between the colonial state and the Catholic Church. Missionaries were “the first ethnologists” of colonial Rwanda. 26 As such, they were the primary ideologues of colonization. For Father Léon Classe, the future bishop of Rwanda and the key architect of missionary policy, the Tutsi were already in 1902 “superb humans” combining traits both Aryan and Semitic, just as for Father François Menard, writing in 1917, a Tutsi was “a European under a black skin.” 27 If the Church heralded the Tutsi as “supreme humans” in 1902, the same Church would turn into a prime site for the slaughter of Tutsi in 1994.

The colonial state called upon missionary knowledge from early on. Soon after colonization, the Belgian state ordered a reflection on Rwanda from the White Fathers. 28 The purpose was to elaborate and implement “race policies.” In response, Fathers Arnoux, Hurel, Pagès, and Schumacher—Church fathers with expertise—prepared anthropological treatises. A consolidated document was then drawn up by Léon Classe, the head of the Catholic Church in Rwanda, and then presented to government authorities. This 1916 document had a wide readership. Not surprisingly, it gave vent to the kind of race thinking that the Church hierarchy had come to hold as a deeply felt conviction. “Race policy” became such a preoccupation with the colonial power that from 1925 on, annual colonial administration reports included an extensive description of the “races” in a chapter called “race policy.” 29 By then, the Church had become integral to the workings of the state: since 1925, annual colonial reports included sections devoted exclusively to reports written by the heads of the Catholic Société Belge de Missions Protestantes au Congo (SBMPC, former Bethel mission), Church Missionary Society (CMS), and Adventists missions. 30

It took Belgian rule a little over a decade to translate its vision of a civilizational mission in Rwanda into an institutional imprint. Central to that translation was the Hamitic hypothesis. Summed up in Kinyarwanda as other than Rubanda Nyamwinshi 31—meaning the majority, the ordinary folk—Belgian power turned Hamitic racial supremacy from an ideology into an institutional fact by making it the basis of changes in political, social, and cultural relations. The institutions underpinning racial ideology were created in the decade from 1927 to 1936. These administrative reforms were comprehensive. Key institutions—starting with education, then state administration, taxation, and finally the Church—were organized (or reorganized, as the case may be) around an active acknowledgment of these identities. The reform was capped with a census that classified the entire population as Tutsi, Hutu, or Twa, and issued each person with a card proclaiming his or her official identity. We shall look at each of these to get a sense of the institutional matrix through which the Tutsi found themselves in a contradictory position, privileged in relation to the Hutu but oppressed in relation to Europeans.

Race Education

If the theory was that the Tutsi were “a civilizing race,” then there would have to be institutions that would discriminate in favor of the Tutsi so as to make the theory a reality. Two institutions were key to ensuring this outcome: the school system and local administration. Of the two, the creation of a school system that could act as a womb of racial ideology was a priority. While the starting point of this enterprise was the notion of Tutsi supremacy that had both justified and sustained Tutsi privilege under Rwabugiri in the Rwanda of the late nineteenth century, its end product was to construct a far more comprehensive ideology of the Tutsi as a race, the “Hamites,” both civilizing and alien. Without a cadre incubated with a Hamitic ethos, it would not be possible to create a local administrative hierarchy steeped in a self-conscious racialized elitism.

The first Western-style school in Rwanda was opened by the White Fathers in 1905 in Nyanza. 32 By 1908, it had twenty-six pupils, all sons of chiefs. In July 1907, Fathers Dufays and Classe had started the construction of another school in Kabgayi. To “surely reach the sons of the chiefs Batoutsi, there has been opened a special school for them,” so they explained as their objective. In 1910, the policy of “favouring the Mututsi of Rwanda” was formulated and addressed by Father Schumacher as a report to the Superior General. The point was underlined by Father Classe in his extended study of 1911. The objective was to turn the Tutsi, the “born rulers” of Rwanda, into an elite “capable of understanding and implementing progress,” and thus functioning as auxiliaries to both the missionaries and the colonial administration. There followed schools, no longer just for sons of chiefs but specifically for sons of Tutsi chiefs: in Nyanza in 1912, Kabgayi and Rwaza in 1913, Kigali in 1914 and 1916, Save in 1917, and Rwamagana in 1919. The obsession with a Tutsi focused education was so strong that the White Fathers decided to move the school in Nyanza to Kabgayi on the grounds that “in Nyanza there were many sons of the Hutu being recruited.” The trend culminated with the creation of the Groupe Scolaire d’Astrida in 1929 by the colonial authorities.

By the early 1930s, government schools were phased out and the missions assumed control of the education system. The system they created had two tiers. The tendency was to restrict admission mainly to Tutsi, especially to the upper schools. 33 But where both Tutsi and Hutu children were admitted, there was a clear differentiation in the education meted out to each. The Tutsi were given a “superior” education, taught in French in a separate stream. The assimilationist education prepared them for administrative positions in government and testified to their preparation for citizenship, even if at the lowest orders. In contrast, the Hutu were given an education considered “inferior,” since they were taught in a different stream, one where the medium of instruction was Kiswahili. The point of the separatist education was not simply to prepare them for manual labor but also to underline the political fact that educated Hutu were not destined for common citizenship. The products of the French stream identified themselves as “Hamites” and those of the Kiswahili stream as “Bantu.”

Emphasis mine.

Mamdani is covering a lot here, so I want to unpack and drill down on a few themes.

He mentions that reforms in Education started circa 1926 and by 1930 the two-tiered system of education was introduced.

Before that, from 1896-1919 when Ruanda-Urundi was under German rule (edit- well, except for Belgian occupation from 1917-1919), and from 1919-1926 under Belgian rule, there were substantial changes in how education was provisioned in Rwanda and Burundi.

If we turn to Alison Des Forges' Defeat is the Only Bad News, she remarks of German education efforts (pp 95):

The Germans frequently lamented the reluctance of the Tutsi to accept European education. They blamed the missionaries, the only real teachers in Rwanda, for discouraging the notables' desire to learn by including religious materials in their supposedly secular classes. Even when the notables decided to send clients to learn language skills, only a few dozen began to study. To train larger numbers of young men who could succeed their fathers as notables, the Germans established their own school, excluding from it all religious instruction. During its four years of operation (from 1910 to 1914), however, the school never attracted the important Tutsi whom the Germans wanted most to educate. At first the Residents attributed the failure to an uninspiring teacher who had been brought from East Africa, then to the decrepit building in which classes were held. Finally, in 1913, the Germans built a fine new school in Kigali and hired two Rwandan teachers. To ensure that the Tutsi would take advantage of these facilities, they pressured [king] Musinga to order his notables to send thier sons to school. Musinga complied with their desires but encouraged his notables to send only their bastard sons, sons of clients, or even ordinary Hutu to study. The Germans apparently never suspected that their crop of scholars consisted of those who would never rule or at least would never rule an important domain. While the outcast of the sons of the elite suffered inside with their ABC's, the real future rulers of Rwanda congregated outside the school to hoot and jeer at them. ....

Musinga and the notables were constantly aware of the challenge that the foreigners might pose to their authority, but they knew how to take advantage of confrontations with Europeans or other Rwandans so that the European presence did not inevitably diminish their power.

So, at first, the Tutsi elite were mistrustful of education offered by the White Fathers missionaries (as an excuse to convert elites to Catholicism) and secular education by German government. That mistrust led the elites to send students from the lower social orders to attend European schools.