That’s not what I read here at all - it says “I should keep this.” Many of us have an urge to keep things, and in many cases we’re justified in doing so. Every person has had the experience of evaluating whether or not to keep an object, and I would guess most people have come up with specious reasons to tell themselves they should keep a thing. Hoarding is just taking that to the extreme. Because this comic is recognizing a tendency in one’s self it seems completely misplaced to say it’s punching down.