There actually has been some gender studies research into the message behind the muscle and if hyper-built bodies are typically gay. (those links are behind pay-walls though and gender studies aren't being taken serious here so let's hear your opinions instead)

In the book Gender, Race and Class in Media they mention how gay men are typically portrayed in the media and how even in The Simpsons the hypermasculine men are typically gay (as well as the flamboyant ones like John or Mr Smithers or a limp wrist, but effeminate gays or twinks are not the point right now because that's more about their styling, tone of voice and mannerisms)

Yet although those are well known tropes somehow TeRPers are always shocked when they post a Chad and get told that he looks gay although they probably would have no problems with calling her a lesbian based on her looks.

So can muscles be an indicator of sexual orientation and who they are trying to attract with them? Or are there multiple factors necessary in order to feel a gay vibe?