You mean the bigots?
What's the problem with antagonizing bigots?
I still don't see the issue. If anything, an outsider and privileged athlete is under little risk, therefore in a perfect position to make the statement.
People usually hold beliefs for much more complicated reasons than that. Sure, the beliefs themselves are bigoted, but when someone is brought up in a specific culture where LGBT rights are widely reviled, what do you expect? They couldn't just push a button and be convinced the ethical thing to do is to support equality. Human psychology doesn't work that way.
I grew up in Saudi Arabia and was extremely homophobic up until a year or so after I joined this forum and got to talk to LGBT people. Many others with a similar background don't have the luxury of knowing English or never have that exposure in a way that would be particularly conducive to change. Antagonism is not an especially useful feeling to engender if you're looking to increase understanding and awareness.
Many people who support LGBT rights are not activists, often only possessing shallow knowledge of how the LGBT population is treated in other countries.
But then one has to weigh the cost of alienating anti-LGBT societies from the messages that raise awareness against the benefit to be gained from increasing awareness among people who already support LGBT rights, even if, as you say, their knowledge is shallow.