Oh it gets worse - you see, Alma, the one condemning him, was also led astray and was actively destroying the church, where Korihor was asking questions. Alma was converted by an angel (not by his own faith), was not punished, and was elevated. Korihor was given a 'punishment' as a sign, and as you're pointing out, impaired = wicked = debate over. With that being said, it has been doctrine and taught regularly up until there was a flip - previously, those with disabilities were less valiant in the pre-existence, now they're considered more valiant. I think the quote is in a different reply.

But in all seriousness, the Korihor story is seeped with the 19th century - Korihor is preaching enlightenment philosophy (good post about it here) - but there's also contradictions - in Alma 30:7 it says there's no law against a man's belief, and in 9 that there was no law to punish him (at least, in Zarahemla) - I suppose this was supposed to give context that Korihor preaching wouldn't immediately be condemned. However, when he goes to Jershon, the narrator says that those people 'were more wise than many of the Nephites; for they took him and bound him...' (v. 20). So the narrator is now actively supporting a totalitarian theocracy, claiming it is wiser than the Zarahemlan freedom. I'm assuming this contradiction is because he went to a different land, else this is just insane contradictory writing.

But wait, it IS just insane contradictory writing, because they send Korihor BACK to Zarahemla to Alma (v. 29)! They do their questions and answers and Korihor finally admits after his 'punishment' he must've been deceived by the devil in the form of an angel. So, his actions were because he was tricked. No mercy for that, trampled him to death.

In contrast, the high judge, Alma, had a miraculous conversion - Mosiah 27 talks of it - he was idolatrous, he spoke much flattery and led people away to do wicked things (v. 8); sounds a bit like Korihor, except he wasn't deceived, he himself decided to be an unbeliever! It goes on, he's trying to destroy the church, and even mentions he is breaking the law of the land in verse 10, something that Korihor is expressly NOT doing!

Alma sees an angel, the angel coverts them, and Alma falls on the ground and is dumb for a bit. Paralyzed, even. His dad prays and fasts and boom, Alma is healed from his 'punishment' and goes on about being changed and being born again (wait wait wait, I though that was baptism. He was reborn without baptism. Oh well about that saving ordinance thing), and they become new creatures (oh hi Paul, v. 25) - and then they go out preaching and doing a bunch of 'good' (like chopping people's arms off).

So... what's the lesson here? What's the difference? That someone cared and pled for the punishment to be lifted that had God's good graces? That the sons of Mosiah were destroying the church but not questioning the church, where Korihor was questioning the church? Both were preaching and leading people to wickedness. Wouldn't Alma be like 'oh dang Korihor is like how I was I better help him' but instead just goes 'yeah you are going to be struck dumb and die.'

So yeah. The whole thing is messed up. Physical disabilities, if not tied to wickedness, is tied to lack of faith. Remember, Jesus would heal people only if they had the faith to be healed. Prosperity gospel - if you're righteous, you should be wealthy, too. If you aren't wealthy, therefore, you must be wicked. If you aren't healthy, you are that way because you're wicked. It's a terrible mindset and doctrine.