I strongly preference the former solution.He used the form twice, in fact, a bit apart within the same presentation. I don't think I know this usage, and I poked around quickly and didn't see it. (I tried both to preference and strongly preference and scrolled through a few.) But it seems like a natural analogical extension of something peevologists love to hate: to reference for to refer.
I expected morphological blocking here — if you have the word to prefer, you don't expect people to coin a morphologically complex form. A contributor to this blog, Monica, refers to this (or maybe she references this) as gratuitous affixation. I'm figuring that it's this kind of formula:
more syllables = more learnedBut I haven't really thought about this.