There's a relatively small limit to actual terms one can apply to a woman, in this context. Most of them are intrinsically sexual, being references to prostitution. Having the villains scream "Slut!" or "Whore!" would have caused no end of sexism accusations, despite Catwoman being at her core a very sexual character. Really, they fall back on ***** because there just aren't many well defined phrases to substitute it with that won't cause even more problems for them.
And note that saying something ridiculously silly like "That damned cat!" is part of causing more problems because nobody will take the thugs seriously. They needed an insult that gets the point across that a bad person is angry, but that won't get the studio slammed for sexism by implying she sells her body for money. End result: They STILL get slammed for sexism.
I think there's a term for this. White Knighting. Taking abject offense at something that really isn't all that offensive to begin with, that has nothing to do with oneself, and leveling complaints and accusations about it as loudly as you can. It absolutely matters who said the terms in game, no amount of arguing will change this fact - angry, sexually frustrated thugs are getting beaten to hell and back by a woman in skintight leather, and you expect them to remain gender neutral? Even if there were overt sexism on display by these characters (which there really isn't), that'd be a GOOD thing, as it would depict utter realism. Put another way. If Catwoman walked into an average bar and started beating the crap out of men, would it be realistic to have a tattooed biker muttering about "that damned kitty cat"? No. It would not. Sexism exists in real life, and trying to pretend it doesn't only makes it worse. Portraying it as coming from lowlife thugs who can't come up with a better insult than gender while getting their asses handed to them is unarguably empowering.
To be honest, I wish they really HAD used overly sexist terms when insulting Catwoman, as it would have reinforced how sexism is itself a crutch used by people who can't handle being beaten by a woman. Instead, they resort to overuse of the word ***** because the studio is justifiably terrified of people throwing a tantrum because they're oversensitive, and can't understand the deeper meanings behind actually addressing sexism in a game.
Which they do anyways.
This is why we can't have nice metaphors.