Unsurprisingly, I have failed at googling up some other examples, but in recent years it has become common (at least in my circles) to use the word "this" as short hand for, roughly, "this thing here is something which is important/i agree with."

I wrote my comment, rather than simply upvoting yours (the parent), because the parent contained several other points which I either don't agree with, or which I thought clouded the message of the part I quoted. In short, I wished to emphasize that one part of your comment.