I don't want to sound like I think some "smart" people are somehow immune to this - I think everyone, regardless of their education or intelligence, is susceptible to this kind of group-think.
It's still not clear to me that I see why shills are such a cause for outrage, at least at a personal level: if a person's critical thinking abilities are impaired enough of people that they'd have their views appreciably changed by shills' voting patterns, the absence of shills just means they'd be blindly following the whims of online mobs. I can see how this is better, but just _barely_.
OTOH, for those who are capable of basic critical thinking, shills don't seem to have much power: if they make good points, then good, if they don't, then no harm done.
I just don't see how why bad comments are somehow worse when they're driven by payments instead of simply the stupidity of a normal person.
I can't relate to this impulse even a little bit, but believe that it's common. That being said, I don't see how its ubiquity makes it any less a failure of critical thinking ability.
The Internet is a pretty hostile environment for those whose epistemology depends on who's behind the pseudonym: it's not clear to me that shills are going to make these people much worse at thinking and processing information than they already are.
The same goes for those who do have appreciable critical thinking abilities: you shouldn't be credulously consuming the thoughts of any random pseudonym, and the same skeptical habits that inoculate you against dumb ideas from unpaid strangers work roughly as well on shills.
It's super creepy