Earlier quoted context omitted.
The NFL never took Colin's entire NFL earnings away from him on top of firing anyone commenting on the initial sitting. I'm pretty sure if they did this, there would be much more uproar than letting him do it and quietly not signing him onto any more teams.
He also didn't start talking about police brutality against African Americans in post game interviews to the media, IIRC.
2. He talked to the media about this as much as possible. 18 minute interview with ESPN: https://www.espn.com/blog/san-francisco-49ers/post/_/id/1895...
3. And he launched an entire campaign around it https://www.knowyourrightscamp.com/