"K's are a necessary biproduct of SLG" is a different argument than "Ks aren't any worse than a fly ball out."
I don't necessarily agree that K's inevitably must rise with increased SLG, but i dont know. And if true, would, to a point, likely increase runs.
I do think MLB has gone well past the point where that balance is justified.
I think, at minimum, hitters should adjust for situation, and with 2 strikes at least, do everything to not K. I believe that will likely increase runs too.
But back to the point...a K is the single worst thing a hitter can do. I don't see how that's controversial in any way. If K's are necessary to further other outcomes, that doesn't change this simple fact.