Heres the bottom line on Kaepernick. I think hes fine, hes not a terrible qb, there are worse players in the league than him. I have zero problem with whoever kneels for the anthem and frankly I could not care less. I do think that the socks with the pig cops and that shit is garbage. But teams do not have to sign anybody if they don't feel his presence will be a positive impact on the team, and people need to accept that and get over it.
Nobody is going to sign him if a backup gets hurt because you don't want a backup QB brining a media circus. Plus, if he is your backup, the second the starter throws a pick they'll have to deal with the "should CK get a chance to start now or is the coach racist?" takes.
Teams like the Jets and Browns, who he would undoubtedly improve, don't want him because he may actually win a few games and cost the franchise a shot at Darnold or Allen.
I do, however, think that if a team in the playoff hunt loses their QB, he could get signed. Hes not a bad player. I actually would sign him right now if I were Denver. I think he makes Denver a playoff contender. Trevor Siemian does not. You could argue Jacksonville too, but Henne knows the system and has chemistry and is better than Siemian.
TLDR: CK is not signed because there is not a situation where he would make sense, but if a team with legit playoff hopes loses a QB, I do think he will be on a roster.