Of course, the danger that a pastor may work to have the government strip a person of a fundamental right based on a private conversation will prompt some congregants to forego potentially beneficial pastoral services entirely.
This was my immediate reaction as well. If you're worried about people turning violent, making them feel like they can't trust anyone is probably the worst thing you can do.
The fact that these activists resort to such surreptitious tactics is telling; it says not enough people agree with them for them to be forthright about their intentions.
Also, I appreciate the article putting "progressive" in quotes. Calling someone "progressive", like "liberal", sounds like a compliment. These anti-gun activists aren't progressive.