Where is the homophobia?
I have several gay friends/relations whom I love in their entirety. But I don't support Pride and I am an ardent supporter of womens rights - which includes being GC.
It has nothing to do with homophobia - you clearly don't understand the issues people have with Pride.
And aside from all that, it's also about personal autonomy for me not necessarily the Pride shirt itself - if someone tried to get me to wear a shirt supporting say, Oxfam or Shelter I wouldn't wear those either.
People should not have to subscribe to anything they don't want to just to appear superficially "on board" with whatever rhetoric is being pushed.
Why would I wear a Pride shirt when I am against men being allowed to enter women-only spaces and take part in woman's sports? Whatever the reasons for this football player refusing to wear it, they are personal to him and it's his right to say no.