Sexuality is not sex. People that are violent towards others in a sexual way do so without consent. You can be hetero and violent, gay and violent, pan and violent, etc. You having violent sexual fantasies is not linked with your sexuality, which is something that you cannot choose. Yes, our patriarchic society is in many ways sexually exploitative towards women and other minorities, but that does not mean being heterosexual is a bad thing. Also, there is no marxist view that says you cannot be heterosexual. That would be an extremely weird ideology.