I very seldom censor comments on this blog, even if the comments are obnoxious. These negative comments are not so different from some of the negative reviews one gets from time to time for manuscripts or proposals or teaching, albeit the blog comments tend to be on the inarticulate and strange end of the scale of negative reviews. I guess I consider these comments to be a natural element of the blog ecosystem.
In some ways the annoying troll comments are like data outliers that you'd like to delete because they make the interpretation of the 'nice' data more difficult, but they are data nevertheless. In some cases, data outliers are important, and in some cases they mean something went wrong with the experiment or analysis or sample preparation or all of the above. Of course, I wouldn't want to hypothesize which of the latter possibilities explains these people.
The phenomenon of aggressively sexist men who frequently read and negatively comment on blogs that have a 'women in science' theme is interesting in a disturbing kind of way. The obnoxious comments certainly reinforce the point that many of us are making about what the scientific/academic culture is like for many of us.
I once got an external review comment from a semi-prominent person in my field in which the prominent person wrote that he 'never' reads my papers because he knows there will nothing interesting in them. I told a colleague about this, and whenever he encounters this particular person at a conference, he makes a point of asking "Hey, have you read that recent paper on X by FSP?" (i.e., me), and my colleague reports that the semi-prominent person always says yes, he's read the paper in question, and then discusses my paper in great detail. As far as I can tell from this secondhand information, this person who 'never' reads my papers has read everything I've published in the past 15 years. As long as he isn't writing any more reviews of my work, it's fine with me if he just lurks there in the background with the other academic trolls, though I know that he could well be a reviewer of my papers and proposals on some occasions. That's an unfortunate part of the academic ecosystem, but it hasn't yet stopped me from writing what I want to write.
9 months ago