If done innocently EG I might sometimes say matt from saverocity and sometimes forget to type that in and use just matt (both backlinking to saverocity) then I don't see a problem.

When it is done maliciously, I think there is a problem. What is wrong with the same person leaving multiple comments in made up names in the same thread, within a short space of time? Well - it gives the impression of critical mass to push one persons agenda. People are pack led, and if 'everyone' is calling out the same thing then people might start following along, without really knowing why - or at the very least start having more and more doubts about the point being raised.

If that situation is being intentionally created by one person with an agenda I would say that is wrong.