I don't think that is quite true. I know several people posted that they doubted it was really Julia, but when she proved it was so, I thought everyone was most welcoming and enjoyed her contributions.
However, what I think did happen is that anything derogatory said about Dorcas' character (especially after the JD debacle) was taken by some other posters (and perhaps even by Julia) to be the same as being derogatory about Julia.
Some people don't seem to understand the difference between a real life personality and a screen character. I hardly think that the real life Julia is a virginal postmistress with Victorian values!
I for one shall therefore continue to criticise Dorcas (if she neeRAB it) without ever meaning to criticise Julia - unless her acting becomes rubbish!