My take is that Sean was dumped because he was a bit too controversial in his personal commentary during Sox games and, perhaps, he was making too much money. Plus, his network jobs on the side had really become his priority and, towards the end, he was really only working 30 or 40 Friday night games per year. Whether he is gay or not, I can't recall any stories about his lifestyle that may have interfered with his job or caused bad publicity.
All executive in professional sports - specifically the NFL and Major League Baseball are deathly afraid that an openly gay person will be in a position of prominence on the field on behind the microphone. Perhaps, they think they will lose sponsors, viewers or listeners.
It makes no sense in 2015 but we have all heard the rumors about the two mentioned above. To quote Hilary Clinton, " ....at this point what difference does it make..."
Can you imagine if Brady came out or even Orsillo and the owners of the NFL or Major League Baseball had to deal with it out in the open. Not making any assumptions about either but used their names as examples.