And yet, perhaps especially in online 'shaming' or targeted critique, the shamer is (presumably) unable to discern that they are really tilting at an imaginary person they have constructed themselves from rather scant information.
Not that it's a new behavioural feature, of course - propagandists and demagogues have relied on this sort of propensity forever. Maybe it's the capacity of internet media to 'present' a person by tiny amounts of information that brings it out.
By 'tiny' we could be talking about a single bit, btw - I've seen plenty of reactions apparently to individuals fully formed in the reactor's mind, despite that their information consists only in the fact that someone clicked 'downvote' rather than 'upvote'!