Nobody is talking about imposing any specific standards or being the quality police. In fact, the only such comment that has been made in this thread is from the other direction in the OP.

I'm just saying that people who haven't prepared themselves to perform in front of an audience probably shouldn't do so, and that I am unlikely to tell them they are doing great.

This is saying nothing about the nature of folk music or whether or not people should sing. Just whether or not they should perform in public. And it's all just my opinion, of course.