That's because she's a parody of that stereotype, she's not just some random chick whose voluptuous body is used for fanservice in the game and that's the only reason she exists for, she's self aware and she enjoys it. I'm very attracted to her confidence, she's like "yes I'm hot and I like sex, deal with it". She being oversexualised is not just a reflection of the way this media treats women, but part of her personality. Bayonetta is very popular among gays, and that says a lot in this industry where every character is designed for the hetero male, the guys are designed as "the men they want to be", and the girls "the women they want to sleep with".
And the game's ******* amazing, it's honestly the best game in the genre imo, I'll buy a WiiU just for Bayo 2 and w101, Platinum can have all my money.