I think most fans would have "sympathy" with Newcastle fans, with the extraordinary lack of success for the money spent, and the quality of players you've had (I don't want to get into a "our net spend is actually about the same as Fulham's" style argument, but you can't argue with signings like Shearer or Owen being of the highest level).
However, the obssession with attendances / best fans in the world / we're a massive club thing is what annoys fans of other clubs. Yes, your support is pretty impressive, yes, we wish ours was that good, but it is done to death somewhat. Oh, and there is a general perception that NUFC are a Sky era club - fortunes improved as Sky started running the game, pretty much loved by Sky ever since.
I'd still say the general "like / dislike" balance is in your favour though, just not anywhere near as much as it used to be.
Maybe it's because that's all what we've got right now.
And maybe if we could get 1 or 2 trophies the fans will matured themselves and not let it show frequently (Not me obviously).