The bigger issue I see is if when these communities become echo chambers which I think is far more toxic. Now if Gab was removing speech that was against hate speech then I think that is a major issue. I see this issue happening more on Reddit where you have community that basically have rules like "if you don't agree with xyz then you will be banned immediately." So the whole thing is an echo chamber in itself.
Also the truth is, these hate speech people aren't going to just disappear. They will persist and continue. The only solution is to counter those people, in dialogue, and keep on them about why they're wrong etc.
Gab is the same but Twitter.
But for all their bitching, they are still active on both in large numbers. Both platforms really only engage in token bans.