Shadowban is mostly a tool to deal with idiots constantly posting attention-seeking comments. If someone isn't smart enough to realize their comments are not being replied to, they aren't the kind of person you really want to contend with. Shadowban deals with people who post comments where the intent is to rouse, not to converse. So much of the time, they don't expect replies, and thus they can continue to post their crap to themselves, and only themselves. I don't think shadowban is polite or nice but it is effective.