That doesn't sound like an offense that should be hellbanned.
I can put it another way: if your comments contribute then your account shouldn't be banned. External factors don't matter at all. Even if you're hitler.
So it doesn't matter if there was something behind the scenes, it should have been dealt with there.
Are your really saying that accounts who sockpuppet and vote-ring shouldn't be banned? (not saying this is what happened to the account being discussed)
Regular-banned maybe. Good potential for them to reregister and stop the bad behavior. Best method is blocking them from getting upvotes but if their comments are productive then they should not be hidden. Hellban is the worst option, even below ignoring the situation. Who cares if someone gets fake points, especially when points are hidden. (Fake votes on submissions are a potential issue but that's not what we're discussing)
I can put it another way: if your comments contribute then your account shouldn't be banned. External factors don't matter at all. Even if you're hitler.
So it doesn't matter if there was something behind the scenes, it should have been dealt with there.