The more common a swear word is the more likely it has been semantically bleached to the point assumptions like this seem (ironically) nonsensical. Few people saying "you bastard" actually give a damn whether one is born of wedlock or not these days (many not even realizing that's what it ever meant in the first place) they just know and use it as "a general swear word you can shout in frustration". Same for bitch, it's certainly possible to use it in the original context and it is still done but it's most often used in a way equally interchangeable with how one would typically use "bastard".

Common swear words like bitch become so semantically bleached context is needed to even decide if it's being used in a negative way at all, let alone with a gendered intent. E.g. "that's bitching" -> is something awesome or not? Is something "shit" or "the shit"? Is it "fucking amazing!" or "fucking 'amazing'"?

I think that if you simply call someone bitch in place of a name, it has become largely but not entirely degendered, but if you call someone "a bitch" it is still pretty gendered.

When you think you're removing sexism, just to bring it back.