Art imitates life imitates art...
Seriously, a great deal of our view of what is "ideal" comes from the stories we entertain ourselves with throughout our lives. That's how values have nearly always been transmitted from one generation to the next -- via fables, etc.
Hero stories tell you what qualities are heroic. Tragedies tell you what qualities are undesirable. We're programmed to absorb information from this shared social consciousness... and at some point in the recent past, advertisers seized control of that consciousness.
We watch a show in which Woman X is held as the epitome of sexuality. We see ads in which Woman X appears strong, confident, in control. We learn to associate the traits of Woman X with desirability... but, you see, ads and shows mostly convey the visual traits.
(See, as human beings, we're also programmed to look for shortcuts. If someone seems awesome, we're apt to assume they are barring mountains of evidence to the contrary.)
Men slowly start to think, "Well, I guess that's what I should shoot for then, right?" Women start to think, "Well, I guess that's what I should shoot for then, right?"
And then the next generation further analyzes Woman X's characteristics, and further distills that list down. If thin is good, thinner must be better. If boobs are good, bigger boobs must be better. Rather than consider the whole, we consider the parts -- Angelina Jolie, for better or worse, is a beautiful woman who happens to have big lips... which therefore must mean big lips are sexy, right?
Video games follow the same trend, if you think about it. Someone finds a mechanic that works, and the next year of games all abuse that mechanic ad nauseum -- because if X is good, X^10 must be super good!
Speeding up the process? We tend to paint the opposite traits as not just "meh," but ohmygodburnthem! How many antagonists in kids' movies are fat and old? Most of them! Heck, we even add deformities, because fuck the handicapped! In doing so, we plant the seeds of a value, which is then watered and fed by the consistent barrage of media, and grows into a mighty oak of absolute certainty.
Neither side (male or female) is entirely at fault. It's our nature, and the media has spent billions of dollars learning how to best manipulate our nature. The best solution remains as it always has: Turn the TV off.