I think maybe because some see their own efforts and see how they run their blogs, they just assume everyone else is the same.

Hehe, I often say similar in that those who cannot produce content worth a damn like to run down those who can by running down everyone who does. Saying that all the content here is crap and that its ALL low quality etc. Its a porr tactic of theirs and yet sometimes it seems to work on some sheep who parrot it back blindly.