After calls for Twitch to address antisemitism on the platform, the site’s hateful conduct policy now includes “Zionist” as a potential slur. Twitch specifies this is conditional: you’re allowed to discuss the political movement of that name, but not “attack or demean another individual or group of people on the basis of their background or religious belief.”
They already banned a swathe of pro-palestinian political streamers in the run up to the US election, so this is likely retroactive reasoning.