I don't have a name for it, but I agree that it should have a name. It's a fascinating behavior. I nitpick all the time, though I don't actually post the nitpicks unless I really believe it's relevant. Usually I find such comments to be non-productive, as you mention.
And yet, even though I often believe nitpicks to be unnecessary parts of any discussion, I also believe there is a certain value to the kind of thinking that leads one to be nitpicky. A good programmer is often nitpicky, because if they aren't they'll write buggy code. The same for scientists, for whom nitpicking is almost the whole point of the job.
It's just an odd duality where nitpicking is good for certain kinds of work, but fails to be useful in discussions.
And yet, even though I often believe nitpicks to be unnecessary parts of any discussion, I also believe there is a certain value to the kind of thinking that leads one to be nitpicky. A good programmer is often nitpicky, because if they aren't they'll write buggy code. The same for scientists, for whom nitpicking is almost the whole point of the job.
It's just an odd duality where nitpicking is good for certain kinds of work, but fails to be useful in discussions.