From the link of this post that you could have clicked on:
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.”
I identify myself as a homosexual.
I’ve heard homo being used in a derogatory way as an insult. That usage should not be tolerated.
Retarded is just a medical term, yet you can use it as an insult as well.
That is what this “specification of conditional” aims at. It’s fine to use the word in a descriptive way, you’re just not allowed to go around angrily calling people “fucking zionist”