It could have been called. I don’t think it was an egregious no-call. In certain situations the context of the rule changes. As an extreme example, a physical, downhill runner like Allgeier, (or Unga, who would physically and effectively use his helmet as an asset with a lot of power) can often be met, tit for tat, and if the defender uses his helmet in kind I don’t think it is flagged. Gray area. The fact that it was a quarterback… yeah, that changes things, even if the quarterback was being somewhat physical.

I save my outrage for things like ripping helmets off of players on the ground after the play is over though.