I'd take that karate chop connecting with a bit of a grain of salt. The convention in the books is everybody gets to tag everybody else at least once in an encounter. Even the top-tier super-speedsters get tagged at least once by the normals in a bout. It's a given in the genre. Maggin tried explaining this as a side-effect of the metagene in that it give the possessor a measure of initiative. IOW, metas have a bigger than normal share of sheer luck for both hitting their targets and avoiding being pulped by superior forces.
Of course, the fact that it connects and Thor makes that remark at the same time is perhaps proof that this isn't the usual meta-gets-to-tag-Thor theme.
Well, that's DC physics, not Marvel, but it is an interesting theory nonetheless, at least to consider. I was never a fan of its application; Johnny Redbeard's GENESIS made me wish DC would never, ever mention the metagene ever again; suddenly human heroism no longer became about guts and gumption, but because a planet blew up at the dawn of the universe and that's why firefighters can rescue little children.
(Which begs the question: why is anybody heroic in the REAL world, where there was no Genesis wave?)
The problem with "the nation that controls magnesium controls the universe" metatheories when applied to superheroism and superpowers is, they make every other origin illegitimate. It wasn't REALLY the lightning and the chemicals that gave us the Flash, but the Genesis wave activating Barry Allen's metagene. Something that was previously straightforward now becomes almost an afterthought.
It doesn't QUITE apply in this instance, because the Superbeast was a super-physical monster that presumably had super-physical agility and speed, which was how he was able to strike at Thor.
Although I did like the explanation that Kurt Busiek had for how even super-speedsters could be struck in a fight occasionally, when Steeljack battled MPH: "I've fought fast guys before," he said, and how he beat him was not a measure of initiative, but the fact that he was able to anticipate where his enemy was going to be and trip him this way. In other words, taking on speedsters by slow guys is more a matter of tactics - and even here, it isn't a perfect strategy; Steeljack noted that this trick would only work once before MPH adjusted for it.
Another way for normal guys to defeat speedsters is by surprise, which is how Captain America defeated the Whizzer in Steve Englehart's Serpent Crown story: throw the shield, have the Whizzer dodge, and let the shield get the fast guy in the back when it bounces.