So the ONLY way to provide a valid criticism is to be able to show examples of one's own ability in regard to the criticized subject matter? That's ludicrous.

Well yes, in the sense that we are all critics all the time - we all say, 'that was a great/lousy movie/book/TV show/meal' etc. etc. Which is expected, and in any case we're entitled as we are the consumers paying money for whatever it was. However, I can't help feeling that someone entering a community devoted to a particular subject and criticising all the other people there, but without a track record of his/her own, whether good or bad, is unjustified and rather pointless.

It would be like me entering a meeting of parents and telling them how bad they are at bringing up their kids - the obvious question is, 'tried it yourself, have you?' (The answer is no, BTW :-)

Steve