My guess in this situation … Mizzou was penalized and was kicking off from the 20. Since that was the same area as a post-safety free kick (where punting is allowed), some people got it in their heads that it was the same thing, so they went with the punt option.
It seems incredible to me that the Mizzou staff would be so devious as to do this intentionally while knowing it was illegal; seems like just a misinterpretation because they were kicking from the 20. But, coaches can be extra-devious in getting around the rules, so maybe … (Speaking of which, did you know there’s still a rule on the books requiring knee pads that actually cover the knees for all players? Given the epidemic of shorts being worn by players nowadays, I bet you didn’t).
Given all that, though, it’s inexcusable for the officials to allow a punt on a post-score kickoff situation where it is explicitly not allowed.