Talking with trolls is a grind, because they're not interested in listening.
Defending/empowering people who are the targets of trolls - eg highlighting Hollywood whitewashing or pointing out that African-American actors don't get the same opportunities as white actors - leads to more of the same fights.
Trolling the trolls makes this a worse place.
Abusing the trolls makes this an even worse place, and also gives the trolls a handy point that they're being mistreated.
Banning would at least send a clear message and makes things here less fight-y and more focussed on movie discussion, but obviously it has its own costs - eg discussion about why people were banned, the perception that people get banned for their 'politics' rather than their behaviour, more personal attacks on the moderator, etc