Similar shirts exit.
And you know they exist since, you know, MJ subbed this here at woot.
Dude. You can blast this for being unoriginal if you like, but Katamari existed long before that guy got the Teefury print AND this is a meme derby - it's literally a derby of overused things. Everything - EVERYTHING - that you see in this derby will be on a shirt somewhere in some form already. They're memes. That's what memes are.
This is an example of choosing an argument just to be one of the people that argues. There are a lot of other things that you could have said, but "similar shirts exist" is not one of them.