Also, all of those examples you gave are of people who are polarizing, not because any one of them are attempting to be silenced. There are a lot of people, especially in the media, who are 100% on board with what Kaepernick is trying to do.
I'm talking about intolerance, where you attempt to shut down people who have a difference of opinion. In Canada, there is a bill being discussed in Parliament that would make it a criminal offense to say anything "directly or indirectly offensive" to a transgender person, which would include things like not using "non-binary gender pronouns," even if it was accidental. The bakery in Colorado that refused to bake a cake for a gay wedding was essentially shut down after a bunch of protests and threats were directed their way.
To the social justice warriors, it isn't good enough to just be indifferent to one of their causes. It's not good enough to not care about or be indifferent towards Caitlyn Jenner's "transition" - you must think he (she?) is a hero and is the most deserving person of an ESPY Courage award ever, and if you don't agree you're a bigot. If you don't passionately agree with them, then you are (insert name here). The rise of "safe spaces" and "trigger warnings" on college campuses are the cases in point of this, and those places are the hubs and incubators of leftist thought.