Interesting topic.
It is no secret that bodybuilding is inherently a homoerotic activity and it is something that you can hardly dettach from bodybuilding. Sometimes its homoerotic nature is deliberately exhibited by bodybuilders on stage, regardless of sexual orientation. Certainly bodybuilders are very uninhibited individuals. You don't have to be gay or bisexual to enjoy this side of bodybuilding just like you dont have to be heterosexual to do things heteroerotic.
It is always rewarding to be perceived as more attractive sexually than the average person and, in my personal opinion, when you become a bodybuilder and when you become a competitive bodybuilder, there is always a percentage of that motivation implied when becoming a bodybuilder. Now, this other motivation is not equally essential for all bodybuilders. Some feel more motivated by this than others. Nothing is absolute.
The question is, why do some people in the bodybuilding world feel the need to claim bodybuilding as a heterosexual property or as an expression of heterosexuality? Why? Activities such as bodybuilding are a human property; not a heterosexual property or a nation's property, etc.
People have the right to engage in bodybuilding regardless of sexual orientation and people have the right to look at it the way that pleases them the most being from a "sportlike" perspective, as entertainment or for its sexually arousing potential.
Even if you could heterosexualise bodybuilding it will never stopped being seen by society as an erotically charged activity because what competitive bodybuilding demands for it to be exerted inherently revolves around this item, that is, suggestive poses, suggestive posing routines and, or course, the exposure of the nearly naked body and a body that is muscular and, muscularity is a secondary sex trait, especially the male body, so bodybuilding will always be a niche.
Bodybuilding is comprised by people who are heterosexual, homosexual and bisexual.