If you had a family member who still lived at home, say a son or daughter, who, keeping it simple, identified as gay , would you still feel uncomfortable putting a rainbow flag on your house? Because in a way, that's what this is. There are gay people in the crowd, there are gay people in the team, there are gay people on your street, and there are gay people in your family.
Centuries of oppresion by religions have made gay people (still keeping it simple) a target. This pernicious ill will has seeped into the collective conciousness, expecially among some of us who don't want to think it through. As a result, some people need our overt support, and will continue to need our overt support for decades to come. This is a common theme, it's not just restricted to sexuallity or identity,
People can choose not to support a targeted minority for whatever reason, the corollary of which will be justified (IMO) criticism. It boils down to how convincing your argument is for the continued witholding of support for unfairly oppresed miniorities, and there're no convincing arguments for that in this thread, as far as I can tell.