I dunno. I think Morty's purging can be both serious and ridiculous, with the gravity of those implications remaining intact. It's almost a darker, bleaker, and more realistic decision to ignore Morty's psychology or frame it in a ridiculously over powered suit of armor. Why would Rick WANT to address it?
He wouldn't, the entire point of their adventures together is to teach Morty, to show him the reality of the universe, to see it clearly and accurately in a scientific way. Maybe Rick knows something about Morty's potential that we don't - remember the autism scene where Morty spouts the numbers? Oh... oh my God.What if evil Morty from season 1 finale is actually OUR Morty but from the future, where he surpassed and killed his teacher (our future Rick)?!
On the other hand, they might not have been better off by the end of the episode. Just with different people in charge. Changing a system is more complicated than just killing the current bastards.