In this context “literally” is being used to draw attention to the perceived obviousness of the information. Essentially saying “how could you not see this?”

In this context, "what's the literally here?" means that the author think the post would be better without it: it's too agressive, sarcastic, demeaning, etc. for example. Hence it's a false question.

It's actually funny because you answered a false question (potentially on purpose). Like:

"What the hell are you doing?!?" "Well Im stealing your car, obviously."

In this context, the verbose explanation to a rhetorical question seems to be the point of the comment, to reemphasize said aggression or sarcasm. It's actually funny because we both are doing the same thing, also potentially on purpose.