I see it now and then, someone posts critique against something, perhaps a bit attacking, and gets a reply from another person in the style of "stop complaining", "you don't know what you're talking about", or "you are so negative". And this response gets turned around with "stop complaining yourself", branching the discussion into nonsense.
Is there a word for when someone brings nothing to the discussion and just complains about the complainer like this?
Best Answer
A noun term to describe the posts is perhaps empty criticism, and this is sometimes now called snark, in the sense that they are critical remarks; to call something pure snark and not snarky is to indicate there's no content other than criticism. They're empty of constructive comments. They're a snarker. I might stick with "troll" as suggested by @RG13, but perhaps the point isn't to imply intent.
In the adjective universe, they are being disdainful, which has plentiful synonyms-- contemptuous, scornful, derisive, sneering, withering, slighting, disparaging, disrespectful, condescending, patronizing, supercilious, haughty, superior, arrogant, proud, snobbish, lordly, aloof, indifferent, dismissive-- and many of those are also good fits for this. You can perhaps stick an -er on the end of one of them and have it fit, but "disdainer" doesn't have the modern feel of "snarker."