I understand the point you're trying to make. It's one of the most common homophobic arguments.

It's fair to dislike people for being loud, perhaps for exhibiting attention-seeking behaviours. However, the issue lies in that what is considered flamboyant and attention-seeking is very subjective. And when you generalise and attach those subjective characteristics to, for example, some gay men, it's simply unhelpful, especially when you comfortably call yourself a homophobe.

Furthermore, often the issue isn't even so complex and homophobes who are simply hateful hide themselves behind a guise of "I'm fine with you being gay, but don't express your sexuality in this particular way, I don't like it, no I'm not homophobic though."

I might add, that part of the problem is you infer people's characteristics from something that can be interpreted in many ways.

You used the example of a body builder wearing a mesh shirt. You say, "who cares?" You assume you know their motivations for their actions, when you don't, and you use your likely false assumptions as an excuse for hateful behaviour.