I mean, Gundy and Brees are able to voice their opinions. If a player leaves Oklahoma St because Gundy voiced an opinion they didn't like, then they should be able to do that as well. Nobody is trying to muzzle Gundy or Brees or say they shouldn't be allowed to say the things they've said. They are free to say what they want, and if others don't like what they said then they are free to leave.
I think that some of the heat Gundy and Brees (especially Brees) have gotten from dissenters to their comments has been a little over the top, and folks are really quick to run to their battle stations, but that's just my opinion. If Chuba wanted to leave OSU because Gundy wore an OAN shirt, or a Saints player wants off the team because Brees said he still doesn't like anthem kneeling as a form of protest, I can think that's an overreaction on their part, but ultimately that's up to them to decide, and they can totally do that without "violating" someone's 1A rights.
What you and others seem to be suggesting in this thread is that other people should not, or should not be able to, take action in response to an opinion they don't like.