Well, yes a group that whines continually about what Wikipedia doesn't host without putting up its own online encyclopedia showing what could be hosted under different editorial policies is indeed the worst enemy of its own arguments for having different editorial policies in an online encyclopedia. Show, don't tell.
By the way, a search engine search on the Clay Shirky quotation you shared without attribution[1] suggests by its top search result that the problem of spam in online communities is ongoing. Jeff Atwood recommends Shirky's article "Communities, Audiences, and Scale" from 6 April 2002 as a follow-up to the article where Shirky introduced the phrase you quoted. As Shirky notes, "Though it is tempting to think that we can somehow do away with the effects of mass media with new technology, the difficulty of reaching millions or even tens of thousands of people one community at a time is as much about human wiring as it is about network wiring. No matter how community minded a media outlet is, needing to reach a large group of people creates asymmetry and disconnection among that group -- turns them into an audience, in other words -- and there is no easy technological fix for that problem."
[1] https://www.google.com/search?q="a+group+is+its+own+worst+en...
