However I can see that it is that sort of minding of other singers business that has reduced folkclubs in popularity.

I don't see that any club setting it's own scope, aims or policy affects the popularity of folk clubs overall and I don't consider setting such things "minding of other singers business".

I am however concerned about people minding other folk clubs, etc. business and I think a fair amount of damage is done on the Internet by people believing their way to run an event is the only way.