Unfortunately, banning abusive or spamming users is basically providing feedback that they have been caught. So allowing them to continue expending effort instead of just creating a new account that will also have to be caught and banned creates a more difficult terrain for the abuser.
"hellbanning" in my mind, though, ought typically be applied to automated spammers and other miscreants, not actual humans with opinions, etc.
Automated spammers wouldn't care if their input was ignored or not. Hellbanning would have a good chance of working only with real humans (miscreants included)
The point of hellbanning is keeping the spam coming from one username or IP, and then not displaying it. If you throw a "You have been banned" message back to a bot, then eventually a human is going to read it, make note of it, and recreate the account or connect from a different IP.
"hellbanning" in my mind, though, ought typically be applied to automated spammers and other miscreants, not actual humans with opinions, etc.