Kaepernick is a SJW leftist extremist snowflake who got what he deserves. If you can't just play football, listen to your coaches, don't embarrass your fan base/city, get the hell out of the NFL. Besides, he wasn't a very good QB anyways.
He worked for one of the worst sports owners ever, and then worked for some of the most clueless sports owners ever, all the while getting the fan base to hand over buckets of money to see loser franchises. Masterful...
Humans don't like each other unless they belong to the same tribe, it's nothing new. There are a lot more tribes these days, and you can be a part of one sitting at a keyboard, it's simply too easy these days, hence the reason it's everywhere.