This is really interesting, both as a topic and as just general history geek stuff. Have you considered the intolerance hypothesis for the spread of christianity (and islam after it)? I vaguely remember reading about it while in undergrad and it essentially says that christianity managed to dominate because it was exclusive, meaning required you only believe in the christian god, unlike other roman pagan religions.
I vaguely remember the last pagan generation being a good source on early christendom as well: https://www.amazon.co.uk/Final-Generation-Transformation-Classical-Heritage/dp/0520283708
Most of your advice focuses on behaviours. This is resonable, but I worry that the problem with that approach is that it deals with the symptom of partisanship rather than the root cause. If you think conservatives and their beliefs are fundamentally immoral and alien, you are likely to behave in ways that make conservatives feel unwelcome. Conscious attempts to moderate these behaviours, while good, will always be imperfect. I think one thing people can do is to read higher quality conservative media sources just to see some of the argumentation on the other side. It's much harder to hate people when you realise they have reasons for their beliefs. Then again, maybe that would just have a radicalising effect.
As I understand it, there are two arguments in this article:
###Sexual Violence in the world###
On funding/spending time on sexual violence reduction programs generally. We all agree that sexual violence is bad. The question is whether there are cost-effective ways to tackle it. Your statistics indicate that rape has a 1 in 208 chance of leading to death. Let's adjust that figure for the suffering rape causes even when non-fatal and say that 100 rapes are as bad as 1 death. We can currently save a life or equivalent for $1700 deworming givewell analysis. Assuming you agree with my rape to death badness ratio, that would imply that a rape prevention program would have to prevent 100 rapes for $1700, or one rape per 17$, with a high degree of certainty to be competitive with our current best option. While I don't think that is impossible, I also don't think there's any strong evidence in the article that this is the case.
As for the more meta level claim that the EA community should devote more resources/time to research in the area. I agree that while there is a lot of attention given to the issue, very little evaluation of program effectiveness is currently being done. I agree that this means there is likely a great deal of low hanging fruit for EA in terms of redirecting funding to more effective interventions. I'm just not sure that sexual violence is a better investment of our time or attention than other problems such as ethnic violence/warfare, drugs, crime, environmental damage, mental health, AI etc..
###Sexual Violence within EA###
On reducing sexual violence in the EA community. I think there are a few major issues with your analysis: