I think FIFA being such a corrupt organization should think twice and think really hard before they start lecturing others on values, principles, or rights.
Gays are welcome to attend the games in Qatar. What the law doesn’t approve of/allow is the promoting/propagating of that life style publicly.
So unless the LGTB fans and the gay athletes are planning to hold orgy parties in the country’s streets , there should not be a problem.
Again the tournament is for sport not for promoting favorite/biased causes.