I guess unpopular opinion but (1) I doubt this person is actually an expert and (2) I think the actual problem is that being anonymous is a coddling blanket that absolves you of the social cost of anti-social behaviors (i.e., acting like a dick) or holding an unpopular view. Obviously anonymity has uses, too, but that is now how it is actually used on the Internet most of the time.

The only reason I bring this up is because I think it is counterproductive to view these people as experts when they are likely not.