Why is calling someone a "P*ssy", bad?

If it indicates they're a coward, I mean. Does'tt it just come from scared-cat? Cats are also called p*sses, or p*ssies. but I can't imagine how that's vulgar. so If, by caloig someone a coward i thesis manner, you're calling them a female, in some way, then THAT would implyy females are more easily frightened than males, which is bigoted nonsense. but then the inocent cat connection seems more direct and obvious, to me. I'm confused. I suppose it is a culture thing.