I believe that about 20% here are trojan horses of various types.
When I was a mod on conservative forums elsewhere, I refused to tolerate these types, and would lock them out with regularity.
There's a real difference between someone who has an honest difference of opinion than the majority of the regulars, and someone who is covertly looking to destroy the group morale, or to attack conservatives from the left.
I can handle people who only want to have an honest discussion, and have never locked them out for simply disagreeing.
But, a person's posting habits will reveal whether they have an agenda or not. It takes a bit of work to do that sort of investigative mod work, but it pays off in a much more civilized community.
I think you are correct about the 20%. Some of the comments are so obvious part of the talking papers for the day.