This is a brilliant question (that was well worth asking twice!). Too brilliant, really, as it exposes a gap in historical literature. To my knowledge, while there is quite a bit that has been written on women, gender and the Spanish Civil War, little of it touches on how gender roles (and their subversion) was perceived outside of Spain. Equally, a lot of the expansive literature on foreign involvement in and perceptions of the conflict neglect gender as a category of analysis. If there's anyone reading this looking for a topic for their undergraduate dissertation or similar, examining gendered portrayals of the conflict overseas would be a really interesting topic. In any case, I'll do my best to sketch an overview from the material I'm aware of.

To begin with the organisation you mentioned, the anarchist-aligned Mujeres Libres, there's no doubt that this was probably the most important single women's organisation in Republican Spain during the civil war. They had expanded greatly during the war, from a small, Madrid-based organisation in early 1936 to having tens of thousands of members in branches across the Republican zone by mid-1938. They undertook all sorts of initiatives across Republican Spain, helping women transition into the workforce in factories and collectives. One of their most prominent achievements was setting up a system of day-care centres that would allow for communal care of children while their mothers worked in agriculture or industry. They were far from alone in undertaking such work – there were dozens, if not hundreds, of anti-fascist women’s organisations active in Republican Spain. Yet amid all these groups, Mujeres Libres was distinctive in viewing themselves not just as a mechanism to channel women’s support in service of government or political party, but in articulating its own message that women’s liberation was a necessary component of the social revolution that had accompanied the outbreak of civil war. In the words of Temma Kaplan, the organisation ‘was unique in that it was also concerned with the personal, ethical, and economic emancipation of Spanish women as well as with their wartime service.’

Their very distinctiveness in this regard is quite telling, and indicates the answer to part of your question – the Spanish Civil War saw relatively limited and incremental changes in the societal role of women, and there were few voices actively calling for more. While women entered the workforce and took on new roles, as might be expected given the extent of the Republican mobilisation for the war effort, attitudes towards women’s place in politics and public life did not shift nearly so far. Even anarchists were inclined to dismiss women, or, as one young member of Mujeres Libres, Sara Berenguer, was to discover, assumed that any women who wanted to talk about freedom meant that she was ‘freely sexually available to them’. Indeed, foreign observers were sometimes dismayed at the extent that Spanish women seemed to be excluded from the enduring patriarchal structures of left-wing politics. One British medical volunteer, Winifred Sandford, was astounded to hear that the only reason she was allowed to sit and converse with the men was because, as an Englishwoman, she had been ‘educated like a man.’ Another, Nan Green, was dismayed that traditional gender roles held firm on an anarchist commune she visited, with women seemingly accepting that they had no right to take part in discussion and maintained traditional gender roles such as only eating after then men had finished. Green, like Australian poet Mary Low, was concerned that Spanish women would be willing to accept far too little emancipation – ‘the little scraps which answered their first call.’ This in turn reflected a broader tendency in the Spanish Popular Front to moderate revolutionary demands in favour of anti-fascist unity – a revolution in women’s social roles, in other words, would need to wait until the war was won. It should also be noted that not all foreign observers were as critical as those quoted above – for some, the fact that Spanish women had responded so enthusiastically to the call to join in the war effort, despite the ingrained cultural attitudes towards women in public life, was proof of the both popular enthusiasm for the war effort and the Republic’s emancipatory credentials. Even then, however, discourse was often tightly limited – gender conventions were being altered but not overthrown, with the role of women redefined to include new duties but within a framework that would do less to offend bourgeois sensibilities.

So, while Mujeres Libres was not exactly ignored internationally – prominent American anarchist Emma Goldman, for instance, wrote for their periodical (which only accepted articles written by women) in December 1936 – they were something of an anomaly, and it’s unlikely that many observers overseas pointed to them (much less any other women’s organisation) as evidence of a radical female revolution in Spain. For overseas observers, a much more potent symbol of revolutionary femininity came from the early days of the war – the famed milicianas, immortalised in images and words in the immediate aftermath of the attempted coup. On the left, these portrayals helped galvanise support for the Republic, proof of the depth of resistance to fascism among the Spanish people. However, even in the most glowing portrayals there could be subtexts that diminished the milicianas as symbols of emancipation. Within Spain, they could be used as tools to mobilise men – the implication being that if women were willing to fight, their own masculinity was called into question if they did not. Moreover, their presence at the front was often softened. The British Daily Herald, for instance, showed one picture of a ‘Loyal Woman Soldier’ not carrying a rifle but repairing a male soldier’s tunic. This was perhaps a more honest portrayal of the miliciana reality – the communists, for instance, organised a women’s battalion for their Fifth Regiment, but relegated it to support work. This did not, of course, stop foreign fascination at such exotic practices – the Times, for instance, referred to it as the ‘Amazon battalion’. In other instances, even the determinedly neutral language of the Times conveyed a sense of unease at the breakdown of gender norms.

Corps of milicianas [militia-women] have been organized, and women, armed and aggressive, take their place in the front line with men. All that womanhood traditionally stands for is rapidly disappearing. Women of the proletariat are not at all perturbed by the fact that in the region held by the government scarcely a church is open, scarcely a priest dares appear in public.

This was among the more measured portrayals of the milicianas from the right. The direct involvement of ‘Red’ women on the outbreak of the civil war was taken as proof of the ill-effects of emancipation on women, with lurid tales of the animalistic, fanatic and wanton behaviour gaining currency, particularly in the tabloid press. Such portrayals were heavily sexually charged; the women themselves of ‘loose morals’, if not actual prostitutes. Many of these stories are of dubious provenance, and they continued to be published long after the brief involvement of milicianasat the front. This can partly be explained by the shocking novelty of women’s intrusion into the masculine world of war, but also doubled as a way to condemn both Republican society and morality, as well as liberalising tendencies at home. In contrast, women under Nationalist rule were represented as ‘true’ Spanish women, virtuous, religious and dedicated to family, proof of the need for traditionalist rule in Spain (and a return to traditional values at home). While women were naturally mobilised to support the war effort in Nationalist Spain as well, care was taken to portray these roles as conforming to gendered expectations – maternal, comforting and supportive, knitting scarves and serving meals. Ironically, the Republic was trying to do much the same thing – as ever, perception was far more important than reality in the eyes of partisan foreign observers.