Its taken a bit of meditation and conversation on the topic, but half-naked men in advertising isn't equally sexist or offensive.
Believe me, I see where you're coming from. My gut instinct (which I'm trying to tame) when I hear something about objectification is "I wouldn't mind someone objectifying me!" - but that instinct is wrong and here's why.
I (straight, white, american, upper middle class, male from suburban christian background) have a shit ton of privilege. Part of that as I understand it is that there are huge double standards in society at large for men vs women. There are things that I can do, which a woman doing would have incredible different reactions an consequences.
To be extreme, if I worked for a company and the rumor was that I had slept with every woman that worked there, it would likely be seen by the coworkers (and management potentially) as being a generally positive thing. James Bond, etc... The rumor of a woman doing the exact same and she's a slut. The consequences of being seen in a sexual light for a man aren't the same as they are for a woman. For men, its a sign of increasing power, and for women unfortunately its of decreasing power.
Actually, it does get mentioned a lot, both in discussion of difference of portrayal, how it hurts men who don't actually want to strive towards displayed image (or, for example, have little chance of developing such a body type), and how it hurts women (because a heterosexual woman will probably end up in a relationship with a guy, and in our culture, it's not a question if he's influenced by the mainstream image, but how badly).