Just my opinion, but I can't consider anything a "slam dunk" without the player's wrist/hand actually coming into contact with the rim. It looks like Grif's fingers graze the rim on this one, but it's still pretty much an air dunk (that should become an offiicial term btw). Was it crazy athletic and fun to watch? Yes. Was it a slam dunk? Not in my opinion
And not only that, but after hearing so much build-up about this dunk, I was pretty let down when I saw the video. I think it does lose something in slo-mo and it's certainly not even close to greatest dunk(s) of all time like some are selling it.