In Mandarin Chinese there is an internet slang, literally keyboarder, which refers to people (especially internet users) who express a lot of groundless and irresponsible opinions but disguised as reasonable critiques. Those speeches are usually much more logical and lengthy than common trolls, but at the end they are based on wrong assumptions and trickery reasoning and are not constructive at all. Sometimes media uses this word to comment bad but real-life (as opposed to internet) criticisms.
Is there a similar word/phrase/internet slang in English?