Any community that cannot survive being questioned is automatically suspect to me. I have trouble understanding why responding to questions with censorship could ever be appropriate.
If you're weary of answering the same questions over and over, you can make a FAQ. I've made plenty of those myself. But if your community has questions that have to remain unasked that you're hiding from, I have to believe that's a problem with your group, not with the questioner.
So I have to disagree: I would prefer to be up front and answer questions, rather than hide from them by banning people.
I agree - so many people have the following reaction to being asked questions: either clam up, or insult you and call you a name for "not getting" the point they are making. It's always suspect to me when someone cares enough about something to comment or post about it, but then doesn't want to answer questions about it.
the term "concern troll" focuses not on what the person is actually saying, but on some alleged agenda. Thus, if misused, it is the perfect refuge for someone who has no counter to the actual argument: simply ignore the points made, allege some other position, and then accuse the other person of lying if they deny that that is what they're really saying. It's a combination of straw man and argumentum ad hominem: make up something to attack, and ignore their actual points on the basis that since the points were made by someone acting in bad faith, they need not be addressed.
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So no, I wouldn't ban them. I might disagree with some burdensome "reform" on the basis of it being burdensome or of questionable value, but I would not hesitate to answer those concerns with argument rather than by questioning the motives of anyone who might question me.
If the question comes up too often, it's a good candidate for a FAQ, not a ban.
If you're weary of answering the same questions over and over, you can make a FAQ. I've made plenty of those myself. But if your community has questions that have to remain unasked that you're hiding from, I have to believe that's a problem with your group, not with the questioner.
So I have to disagree: I would prefer to be up front and answer questions, rather than hide from them by banning people.