concern troll troll
A person who pretends to support an ideology, often taking it too far, in order to discredit the ideology. They accuse someone of being a concern troll for simply bringing concerns or not being fully committed to the ideology. Their goal is to make the ideology look dogmatic and extreme to outsiders, as well as encourage paranoia, tensions, and infighting among supporters about who is really a supporter.
"In our last 'Flat Earth' meeting, David brought up a concern about how we would explain the moon's movement if the Earth was flat. Emily said that she was concerned that David was a concern troll because obviously the moon doesn't exist. I stated that I have concerns that Emily might be a concern troll troll and was trying to discredit our movement, but then she also accused me of being a concern troll. The rest of the meeting consisted of everyone arguing about who was really a flat Earth believer. Stacy tried pointing out that she was concerned we were getting nothing done and we should focus on our agenda, but Tom called her a concern troll for trying to distract everyone from their concerns that there might be concern trolls and concern troll trolls among us."