Unless you are very close, I'd be wary of conversations that can come across as expecting an individual to be the voice of such a large group. Every group has a mix of perceptions, no faith is a monolith.
Every institution has issues. Islam has multiple institutions within that which use the texts and the power of being an Islamic institution to do vile things. It should be challenged just like if it was any other institution, whether or not the root of it is from Islam or another cultural institution that is using Islamic institutions to have the power to do so.
It makes no sense to go on about early Islamic practices to today as a reason why Islamic institutions shouldn't be challenged.
How is it the religion that's the problem.
Because religions include social institutions that give people social power. That social power uses the religion to keep their power and sway others people and at times other institutions into certain actions. Saying those who do evil are just innately so is hubris that you could never be evil and erases how institutions, religious and otherwise, incentivise our behaviour.
Similarly you’d never think Christianity also believed in child marriage (for women) because the Vatican and CoE have ensured Bible translations don’t include it.
Plenty of corruptions within churches and people using the power of Christian institutions to do vile things, but it has nothing to do with the Vatican or CoE ensuring anything about Bible translations these days. It's been standard practice for some time for translations to involve people from a range of religious and non-religious backgrounds. The Vatican approves of many translation they had nothing to do with. The CoE has little involvement in translations. While there has been issues with both standardizing the use of being open on which translation they're using when quoting, they aren't really hiding secrets about child marriage. It's quite there in the texts, as it is in related texts. It's also there quite blatantly in Jewish texts that Christianity uses part of - one of the most obvious examples is Moses gets really angry that in capturing a settlement that boys and women were saved, and orders the murder of everyone but the virgin Midianite girls, because God was pissed at an event with a Moabite woman. This is oddly a rare example where Moses was very in his rage and God wasn't (most of the time it was Moses trying to have God show mercy), and this is part of a chapter that earlier discusses that women captives were given one month to mourn their losses before they become wives (and in other Jewish writings, if they continued to mourn, they could be executed). It's there in any translation, none of the churches or synagogues hide it, most won't argue it was a good thing we should emulate, but gloss it over a historical act of war that shows how they had fallen in war from what is called out in the text as the typical practice of just slaughtering all the men.
It's what those who get their social power from those institution are doing with what is in the texts that matters a lot more than texts from thousands of years ago having vile stuff in them.