Based on recent experience on some big websites for which I write, I am inclined to agree (around 90 percent, anyway). In one particular case relating to a health care matter, a commenter seemed to delight in—paraphrasing a certain Jesus of Nazareth—ignoring the "plank" in his argument, while scrutinizing the speck in mine.
I have encountered this often, among what I tend to call "stat freaks," those who would endlessly and misguidedly analyze the quality of data while missing the obvious point of the research. Ironically, stat freaks tend to criticize the few good studies out there, while ignoring the junk science.
On political websites, you might see the "regulars" gang up on a newbie, just for being a newbie.
This sort of "engagement" probably scares off more visitors than it attracts.