The person putting everyone on ignore cannot stop everyone else from continuing to converse on the topic, or otherwise engage his arguments. But he is certainly shutting down his engagement in debate and merely engaging in soapboxing or screed regurgitation.
You know, this isn’t really a big issue. After the Ignore Bot has ‘banned’ everyone willing to actually try to discuss things with him, his posts and cites sit out there, to be replied to and disproven by all the people he has on ignore. He never sees the replies, or the opposing cites, and won’t (can’t) respond. Lurkers reading see his ass being handed to him, repeatedly, and see him with his fingers in his ears going “I can’t hear you!” What is the lurker to conclude about the quality of his argument?
It’s a self-marginalizing behavior. Let him do it. It means you win.