Because there might not be any gay footballers have you ever thought of that?
As said what a person does in the bedroom should be nothing to do with anyone else, a man can hold hands with another man down the street for me, i won't look twice, as a straight guy it's nothing to do with me, as long as they are respectful to towards me and my sexual origination as a straight guy.
As for the highlighted, they don't though, a lot have come out from the woodwork in the last 10 years because society has become more tolerant but my experience with gay people is they have to put in the faces of straight people, You see it all the time in clubs, gay men prancing around you, no regard or respect that you are straight. Why do that? A lot of it is 'attention' something a lot of gay people crave (even negative attention), even had gay men coming up to me offering to buy a drink and still pushing it when you tell them your straight.
Then you see gay pride, marching in the thousands wearing nothing but a g-string string on, why not walk with pair of jeans and jacket on like a normal person if they want to be seen as 'normal', why wear next to nothing? Again attention, wanting respect but not showing respect themselves.
As for football, all the LGBT community want is a puppet to sit in front of the camera putting who they are in people's faces who have no interest in that.