The Raiders paid him like a #2 DE... but he is comfortably a backup with Yannick Ngakue and Maxx Crosby on the roster.
I'll follow your second point by asking why - in a society where the generation who plays pro sports doesn't care about sexual orientation - is Nassib the only male pro athlete in a major sport to come out? Probably not the teammates who already knew... it is likely the potential harassment from fans who have not accepted the fact society has changed and left them behind.
Jason Collins in the NBA.
I'm not sure if there are even many closeted NBA players, but without getting into a debate about the other issues related to it, it's widely believed that Magic Johnson is/was bisexual.