But male and female forms aren't portrayed with the same outlandish proportions - male super heroes are drawn as a male power fantasy, whereas female ones are as a male sexual fantasy.

As for the fictional argument, it doesn't really hold up. Fiction means the story isn't true - not that the people in it aren't. At the root of super hero comics is the question "what would people do if they had super powers". But they're still supposed to be realistic people who's actions and motives we can understand. If you apply your "anything goes" policy to non-sexual things, would you not expect to be confused if a character sometimes talked in gibberish or their limbs came detached - but no one else reacted to it or it wasn't explained within the fiction?

And then there's the prevalence of it... bottom line is, if you don't like it, and don't buy, there's very little else to buy.