The Streisand Effect implies that the subject did not want the publicity but got it by trying to hide or cover up something. Here Twitch wants people to see that they are taking action. Now if the publicity leads to additional trolling of their platform thus exacerbating the problem, then you could make an argument that this scenario fits the Streisand Effect.
I didn't know. The Streisand Effect absolutely applies, at least in my case.