I guess your question is: is it okay for me to RP as a psychotic gay misogynist vampire. Which, yeah, it’s fine. If that’s what you want, and your partner is cool with it.
The thing is, other people are also looking to have fun in their RPs. Their idea of fun might not involve having brutal violence enacted on their character just because their character is female. Or to have misogynist content in general. This is something you’ll just have to discuss with them. You’re not entitled to RP the exact thing you want with everyone just because you enjoy it.
Same goes for the fandoms. Not everyone likes the things you like. No one is forced to provide the RPs you want.
I don’t understand. It’s only a problem if you see it as your right to get everything you want in life, from every person you meet? Some people will not enjoy this idea, in which case I don’t see why they should be forced to RP with you.
You might find someone happy to RP this with you, it’s not against the rules as far as I can tell. Just don’t expect everyone to enjoy it. You may in fact get some people calling you out as being sexist.