While I'm not a parent, I know a married couple who told me about giving their teen kids "the talk", which was about STD protection and an edict to use rubbers.
But, I think you're asking us to weigh in about your own parents' choices, and it's not our place to do that. They get to decide their own comfort zone. It sounds like they are reasonably enlightened and that's the best you can hope for. It also might be that they don't want you disengaging too much from the rest of the household when you're at home, as opposed to trying to be controlling about your sex life.