Generalising is notoriously difficult in historiography, for good reasons. When we discuss the extent to which an idea was popular, for instance, what we are really discussing is the relative number or weight of the individuals who held that idea in the population. So what I will do is providing some examples that, I hope, reflect at least general trends. As for what, for example, Arab masses in Hijaz or Syria that did not read newspapers believed, I will not have much to say, regrettable though this is.

Mehmed Akif (later Ersoy, when Turkey adopted the Surname Law in 1934) was one of the most prominent Islamists in the Ottoman Empire. His worldview aligns with the Salafis and modernisers across the Muslim world, especially the ones in Egypt like Muhammad Abduh. Akif was deeply suspicious of nationalism and for this reason, though he was ethnically Albanian himself, he opposed the Albanian revolt and independence in 1912. All Muslims had to come together to survive at this age of increasing Western dominance and oppression, he felt. But Akif was no mere opponent of the West. He was invective towards 'the traditional Muslims' for their 'laziness' and the way 'they left the righteous path of Islam'. Muslims would be saved only if they embraced the technical knowledge of the West and combined it with the 'moral superiority' of the pure Islam.

There are certain events during WW1 that makes it clear that Akif did not think it was such a problem to fight a jihad alongside Germans (and Austro-Hungarians and Bulgarians). First, we know he supported the Ottoman war effort wholeheartedly. He wrote a series of poems, most famously on the Gallipoli Campaign, where he likened the Ottoman soldier to the 'lions of Badr', which is a reference to an early, well-known Islamic victory against Arab pagans, the Battle of Badr. In concert with the Ottoman secret service, Akif also visited Germany with a quite specific goal in mind: to convince Muslim prisoners of war in Germany to join the Ottoman (read Muslim/Caliph's) Army. These efforts were only partially successful, among Indian soldiers from British ranks and North African soldiers of the French Army, for instance. What is certain is that a convinced Islamist like Akif did not deem it unacceptable to collaborate with Germans for the victory of jihad.

The case of Rashid Rida, an Arab Islamist from Egypt, more complicated. Just like Akif, Rida drew from the work and worldview of Abduh. While Akif was initially more supportive and a bit more patient with the powerful Committee of Union and Progress in Istanbul, Rida had much less time for these 'freemasons', as many Arab intellectuals came to see them. From 1912, he became one of the intellectual leaders of the Arab 'decentralisers' in the Empire. He had initially considered Germany as a less malign Western power and as a potential ally of the Ottoman Empire. Many Ottoman Muslim intellectuals initially shared this belief, no doubt bolstered by the fact that Germany was not a major colonial power over that ruled over Muslims at the time, unlike the Entente Powers. By the time of WW1, however, Rida was hopeless about the Ottoman Empire, in part because he felt the Empire was actively being used by the 'illusive' alliance of the Germans. He believed that Germans did not care about Muslims at all and their self-interested alliance could scarcely save the Ottomans. Therefore, he went on to support the Arab revolt. Interestingly, however, Rida's opposition to and rejection of the Ottoman jihad seems to have less to do with the alliance with a Christian power. Rather, Rida opposed it by pointing out the 'anti-Islamic' character of the CUP and the uncivilised character of the war itself. So even if the alliance with a Christian power was something distasteful, Rida does not seem to have considered it a 'gamechanger' in its own to make the Ottoman jihad unIslamic in itself.

A number of figures did portray the declaration of jihad as a basically German decision, though. These include Aga Khan from India and the bey of Tunus. The caveat here is that the former was a traditionally pro-British figure at the time whereas the latter depended on the French. So it is not clear whether they really believed in what they said. We know for certain that the British officials attempted to portray the jihad as German-inspired and therefore illegitimate. In 1914, for instance, they discussed with Sharif Hussain of Mecca, the eventual leader of the Arab Revolt, whether the armed presence of Germans in Istanbul made the declaration of jihad null as the Caliph could well have made the declaration under duress. It is more likely that Hussain's decision to initiate the Revolt had more to do with his realpolitik calculations and his dislike of the CUP leadership than the German role in jihad. Still, George Antonius' The Arab Awakening of 1938 recognises the German alliance as a factor weakening the argumentative power of the Ottoman jihad (p. 135), without giving clear examples of who were influenced by it and how.

So, generally speaking, I do not think the alliance with Germany was a primary reason at least among Muslim intellectuals to reject the jihad. The ones that saw it as valid could even go to Germany to convince Muslim prisoners of war to join the war effort. The ones who rejected the jihad generally had different ideas in mind, though Rida, for example, did dislike the close alliance (read de facto colonialism, according to him) on the Ottoman-German axis. But the beauty of history is there are as many positions as there are individuals. Just like it is today, there are people who are motivated by ideological, cultural or religious factors, who are pure idealists ready to die for their ideas. There are also pragmatists who care more about their gain and motivated by greed. If one type of a factor (say given religious considerations, in this case) did not motivate many individuals in one case, this does not mean it has never motivated anyone.

Sources:

Umar Ryad, 'A German "Illusive Love": Rashid Rida's Perceptions of the First World War in the Muslim World' in Jihad and Islam in World War I: Studies on the Ottoman Jihad on the Centenary of Snouck Hurgronje’s “Holy War Made in Germany", ed. by Erik J. Zürcher (Leiden: Leiden University Press, 2016), pp. 305-28.

Mustafa Aksakal, '"Holy War Made in Germany"? Ottoman Origins of the 1914 Jihad', War in History, 18 (2011), 2, 184-99.

Eugene Rogan, 'Rival jihads: Islam and the Great War in the Middle East, 1914–1918', Journal of the British Academy, 4 (2016), 1–20.

George Antonius, The Arab Awakening: The Story of the Arab National Movement (Philadelphia: J. B. Lippincott, 1939).