As someone who has been using reddit and frequenting r/all for over 10 years orso, I dont know what you are talking about. Either make you point, or just don't make such comments. They add nothing.
I think one could argue that your comment adds much less to the conversation. It's basically just "you're wrong, because I said so."
Maybe - since you have a decade of material to draw from - you could offer a counter-example? I think that would be more conducive to discussion than "don't make such comments."
It's far more than that. The OP said "you know exactly what" - and the comment disproved that, by not "knowing exactly what".
Also, how is the comment supposed to refute a negative? A negative that wasn't even a claim to begin with but rather a vague gesture towards some conspiracy (?).
And I am refuting the refutation by "knowing exactly what". Turtles all the way down.
Do you see how silly this is yet? The comment you are defending is - logically - about as valid as not saying anything at all, which is exactly what they told the OP to do.
With a specific claim demonstrating a contrary phenomenon, one would think. "Vague claims" aren't some rhetorical ace-in-the-hole. They can be argued against, presumably better than "you're wrong, and you should feel bad."
Maybe - since you have a decade of material to draw from - you could offer a counter-example? I think that would be more conducive to discussion than "don't make such comments."