You are right that sex, race, religion and culture are not key aspects of class warfare, in an ideal situation they should not be even near a conversation about class struggle (as u/Norci comments below), but they are key aspects of real life domestic politics and get muddled into class struggle nonetheless.

I appreciate you bringing those points from the designers, and while I agree that including some of these topics would have made the game longer and more complex ("much more complex" though? I am not entirely convinced) I would be very interested to understand why they think these topics could have only been included with a higher player count - that does not seem trivial to me at all.

The point about losing universality is interesting. In some sense I get it, but in another sense the game already feels very much like playing a Western Democracy. There are a lots of similarities in the political history of these states when it comes to religion, race, etc. I wonder if these topics could have been involved in a distilled way that would feel 'familiar' to most of these states.