'artistic and literary material is frequently quoted as anon'
I must say I'm not really aware of this - maybe I don't quite know what you mean by it?
Also I'm not quite sure why a person would want to remain anonymous if they stand by their views, unless they're the type of views that are going to get them into trouble. (I don't necessarily think that 'Hob' and 'Chris Collyer' would have wanted their real names kept out of the paper - maybe they weren't asked or contacted).
I don't think putting people's pseudonyms into inverted commas implies disrespect either, it's just a grammatical acknowledgement that they are pseudonyms, surely.