Another thing, if Sam was drafted as, for lack of better words, charity-reasons, if Michael Sam did not really deserve his pick in the draft and I can’t judge that, it would mean he would have taken the place of another aspiring football player. As I said, I don’t know that but it might be worth considering. As it stands, I suppose what are called “unsigned free agents” still go to camp to try out. I have seen a few lists of “unsigned free agents”.
A seventh round pick is just a small step above un drafted free agent. There’s no guaranteed money. They still have to make the team and few do and mostly on special teams. Sam won’t be a ST player.