First of all, not everything that's ok in an entertainment medium (TV, movies) is ok in a professional setting. I don't think presentations like these would have been appropriate at a conference of lawyers, doctors, artists, or biologists, either.

That said I think this also has to do with the extreme gender imbalance. Tech conferences are very male-dominated. I think the first photo here really gets this across, of the restroom line at another conference in SF:

http://www.theatlantic.com/technology/archive/2013/06/ridicu...

Imagine that you're a woman and you're walking to the restroom, past a line of 40 or 50 men. And now, imagine they've all just seen a "joke" presentation about staring at women's breasts. You might feel like a bit of a target, don't you think? It could be pretty uncomfortable.

Whereas, if we had a gender-balanced industry, and if we had, say, 47 men in the men's restroom line and 43 women in the women's restroom line, a presentation like the ones we're discussing would still be offensive and inappropriate, and still really not ok, but it might at least feel less personally threatening.