This is debatable whether if men are objectified in art or not, though this is something I’m sometimes guilty of (or close to it) sometimes. But I think in the context of how nuanced objectification is beyond simply wearing skimpy outfits (in some cases like certain sports, this may even be justified).
It’s also got to do with the posing as well as the focus on certain body parts (I sometimes have a feeling that certain characters could get away with certain things if/when they’re depicted as having very uncanny valley anatomy to lessen the objectification at least in some cases).
I think the difference, though sometimes grey, is clear between Boris Vallejo’s artwork and those of David Gregham, Aleksander Vishnakov and Tony Butcher. Though not always the case, I get the impression of nude men in Vallejo’s artwork as being involved in actual physical activity or at least having body language that goes beyond passive sex object.
The latter three sometimes have very passively posed men. Vallejo may sexualise his men but not to the same extent the latter three do, especially as they either make the men be as passively and seductively posed as female characters do (Vallejo’s men are often almost always engaged in physical activity).
Gregham and Butcher all seem like watered down versions of Robert Mapplethorpe (if you know what I mean even though Dianora Niccolini’s not any better either) whilst Vishnakov shares Mapplethorpe’s BDSM fascination. Vallejo, by contrast, is actually closer to the artists who do heroic nudity a lot. I mean his male characters are often warriors.
Or at least involved in physical activity (though it can be argued that he’s not any better however by depicting them as macho seducers of women sometimes so). This may not always be the case but I still get the impression of Vallejo, whenever he does feature men at all, even when they’re naked they’re almost always supposed to be heroic or warlike.
(Or at the very least engaged in physical activity, much like his late rival Frank Frazetta.) The men in the latter three’s works are (much) likelier to be passively and seductively posed characters.