I agree with your underlying point, but due to a weird quirk of Wikipedia history, Catholicism in particular was for quite some time way over-represented; in the initial land-rush to populate Wikipedia with content, they grabbed a number of out-of-copyright encyclopaedias whose text were already in digital form, and one of these was an old edition of the Catholic Encyclopedia from 1913. With the strange result that the very most obscure topics in Catholicism were actually pretty well-covered, though often with information that was a century out of date! Even now you can find articles that have been barely tweaked from their 1913 form.