it pretty obviously misses the main explanatory factor which is religion.

Not sure this is such a massive factor, iirc similar incidents (if we're talking about organised or semi organiesed groping and then sexual assault of women at large public gatherings) are at least relatively common across many places in the third/developing world, I can think of India, parts of Africa, some parts of Latin America (though this is much less prevalent and extreme), something partially comparable was at least partially true (though much less extreme even than latin America) of Italy and many Mediterranean European countries also in the (fairly recent) past.

imo it seems to be associated with a load of things; relatively poor countries, endogamous marriage and marriage practices aimed at preserving family wealth over romantic comparability (which itself seems to be associated with distant and adversarial gender relations), high 'bride price' and a large number of young men who essentially cannot 'afford' to get married or have a sexual relationship, also with a rigid gender system, with 'honour cultures' (rather than shame ones) and the various taboos around sex and who is to blame for x, y and z sexual action, with the relative low status of (young) women and also with a kind of Victorian 'separate spheres' ideology where men seemingly reserve various public spaces for themselves and women are supposed to have various 'private' ones to congregate, this is associated with men seeking to exclude (mainly young) women from social spaces and it ties into the shame culture and taboos.

I think that religion is a factor and double one in that ethnic/religious chauvinism, stereotypes about 'outgroup' women and chastity or modesty etc, also ones about 'outgroup' people in general being less worthy of empathy/sympathy etc and close knit communities closing ranks around crimes seem to play a role in

But I'm not sure if it's the main cause, similar things seem to be true of other religions in various social contexts and I think it's crazy to just pin it all on islam, which is a relatively hetrodox belief system.