Uh... no.  Kaepernick wasn't good enough to play in Denver, an assessment made by Elway before Kaepernick eevr took a political knee, and after SF decided that he wasn't good enough to be their QB.  He wanted low-tier starter salary but had no leverage, when Elway wanted to pay a veteran backup.  The NFL, with a very high fraction of African-American players, is ultimately a meritocracy: if you can play, you will.  Michael Vick was employed by 3 NFL teams (granted not that well) after serving time for running dogfights, an act more heinous to many than a political statement.  Tom Brady (and his owner) openly supported a Presidential candidate that many on his team boycotted after winning the Super Bowl.  Were they suddenly free agents, Martellus Bennett, LeGarrette Blount, Devin McCourty and Chris Long would all have multiple job offers tomorrow despite showing an American President what some would call disrepect by their boycott (as would Brady, of course).  Because they can play.