I vote no to censorship.
I am also very much in favour of ignoring deliberately provocative or inflammatory threads. I am sure there have been several posted recently just to see what reaction they trigger.
I think there is a tendency to be too analytical here. Why has someone decided to leave, etc. No group or individual can hope to be all things to all people, but I think that Mudcat does a pretty good job. If you have an enquiry about music, then someone will instantly help you out if they possibly can. Therefore Mudcat is fulfilling its basic function. A diversity of threads is what stops it from becoming a sterile environment. Does anyone honestly expect to find only threads which are of interest to them? Even if only music threads were allowed, this would hardly be the case, as 'folk' music is such a generic term.
We all have the choice of which threads to read & which to ignore. It seems to me that by entering into endless discussion over whether there are too many non-music threads, whether someone was being too personal/offensive/inflammatory etc, is not only perpetuating but also increasing any problems.