It seems the specific question of what it was that got DSP shitcanned, and how reasonable it was, is a pretty popular discussion, but I really wouldn't trust anything DSP says about it. He signed a contract that (assuming the language is the same as the affiliate agreement) reserved Twitch's right to terminate it with or without cause. They have never, during the entirety of this debacle, been required to give him a reason, whether it makes sense to him, or makes sense to us.
He can rage all he fucking wants, but the methods for remedy are pretty straightforward: he can go to arbitration. By signing the agreement he waived his right to a jury trial even if it goes to court. He can scream and howl until the ends of the earth, but that's the contract he signed. If he didn't agree with the terms, he shouldn't have fuckin signed it.
Read the fucking documents you sign.