"Hockey IQ" is not a measured stat in the NHL, so the claim cant refuted. It's a buzzword like "toolkit", "intangibles", x player is so "raw".
More importantly, that's not at all how the burden of proof works. You cant make wild claims and then say, well if you cant refute it, I win. The guy making the claim needs to provide evidence, if he cant then the claim doesnt need to be refuted.
That's how all the religious people get by, "well you cant prove god doesnt exist!!"
And no, MacKinnon having more points last year does not in fact prove he has a higher hockey IQ.