I think that you misunderstood what I wrote.
People think that it is wrong to make unkind comments about the physiques of thin or non-thin women. But people seem to have no problem with anybody making unkind comments about the physiques of female bodybuilders. Why the double standard?
It is not so much a double standard as showing that the ratio of people who'll mock and people who will not condone the mocking is skewed. The scenarios listed all have people who believe it is wrong to make unkind comments to ladies within those three categories, but the voice for those of the body builders is drowned out by the voice of those who recognise that in an attempt to be the best certain individuals use steroids to give them an edge. It happens in male body building (and is commented on) and it happens in female body building. Like with those who make the comment that very thin women may be starving themselves (in some cases it is valid, in some cases it isn't) and those who say fat women are obviously greedy and lazy (again sometimes valid, sometimes not) this happens with body building.
Again the difference is that whilst there are plenty of people around who can say "well, i'm thin and I don't starve myself, I find your comments offensive" or those who can say "those comments could negatively influence an insecure individual and therefore cause their eating disorder* to worsen as they delve into the only comfort they know" it can be harder to refute negative comments thrown out about female body builders just because they do not occur at the same frequency as fat/thin women in the general populace.
You also get those who will gladly make such comments because these women do not conform to the stereotype of how a woman should look. You get people making comments about women with the slightest bit of muscle definition so the body builders are pretty much a prime target for this sort of negativity. People generally do not like change, certain physical attributes may be mocked but they are considered normal enough for people to acknowledge that mocking them is ill-advised. If something is different from the norm people forget their manners and just go for the jugular, even nice people.
Not to pick on North America but sometimes the American tourists are a fair bit larger than individuals considered Fatty McFatties here, and by fair I mean much larger. Like with the body builders everyone forgets they're not supposed to pick on fat people and suddenly no one can stop staring/commenting/snickering because whilst they are used to fat individuals they are not used to fat individuals over a certain size. The fact they're a tourist helps, you add in the fact they're not part of the community (everyone hates the majority of tourists, even those whose businesses rely on them) and they are fair game.
Anyway.
Double standard? Maybe. If there were more female body builders in the general community then it would be less acceptable to mock them. Everyone acknowledges it is wrong to mock someone due to their ethnicity but if you are a Romani people forget themselves because you're fair game. Anything outside of what is understood and accepted by general society has heavily biased ratios when it comes to understanding what is acceptable and what isn't.
In regards to using steroids as an excuse for making negative comments ... if the comments are medical and express genuine concern over the effects the steroids have on the body then fair play. If they're used as an excuse to simply call them freaks and whatnot ... that's not cool people, just not cool.