Both the 49ers and Seahawks had prominent players speak out loudly against openly gay football players in their locker rooms. IIRC, it was Chris Clemons in Seattle. Granted, Clemons is probably gone this offseason, but there is obviously a homophobic culture at work in NFL locker rooms and black culture has famously done little to hide their distaste for it as well. The real question becomes, can a locker room handle it? There is a risk of distraction. That isn't Sam's fault, it's just the way the world works right now.
I'm very impressed by Michael Sam's courage. To make this announcement knowing that it could potentially jeopardize an NFL dream takes some serious guts. This isn't some first round talent. He's a mid-round guy, an DE who stands the same height as Nick Reed. Serious balls.
I actually kind of hope he isn't a Seahawk. It's so hard for mid-late round guys to make this team, and I don't want to hear accusations of homophobia when he's cut. Very much rooting for him to make history though.