Allowed by whom?
Not allowed by the same common sense that prevents one from criticizing Batman, Sherlock, or Game of Thrones. Also, not allowed by the Daleks. They get testy.
I think you got it backwards. The Daleks would require you to hate The Doctor.
I don't find this 'It's True' at all... whenever I share my criticisms of the series with other fans I usually find them quite open to my comments. The Doctor Who fans I know all happily accept that it is flawed.On the other hand, whenever I try to say I dislike 'Arrested Development', I'm always told to watch more because apparently the cure for disliking the show is to watch more of it... watched the first bloody season this way... I have never met a fanbase more rabid about something where the flaws seem so apparent.
Have you tried expressing disinterest for anything related to Josh Whedon ?"How dare you to dislike buffy if you haven't watched ALL the episodes yet !?"
I find that too, regarding Doctor Who fans. I'm not sure there's anyone out there that thinks the show is all perfect, all the time. It's which parts are great and which parts are garbage that you'll find violent disagreement on.
'Whovians' do my head in. I've always watched the show, but now I and most of my friends only watch it in the vague hope that it will suddenly become less terrible. All the little catchphrases and quirks and general 'WACKINESS!!!1!' seem so obviously pandering to the die-hard fans. We could definitely do with less of the sudden-plot-twist-magically-solves-everything, as well as the Doctor having the personality of a hyperactive, crack-addled puppy. Although John Hurt is awesome, as is Peter Capaldi. So we live in hope.
It depends on the who fans. Old school whovians know the show is flawed, and love it for those flaws and are even proud of those flaws. There's nothing they like discussing among themselves more than "which is the worst doctor?" or "which is the worst companion?" or "K-9: yay or nay?"New who fans tend to the other extreme, and can be quite rabid.