Fair, it might have just been a misinterpretation on my part on his age. We'll have to wait for more details. @Ludgu
Except that's wrong. There's plenty of types of therapy that have shown significance at managing Antisocial Personality Disorder, such as group therapy, cognitive therapy, behavioral therapy, and family therapy if the individuals are young enough.
The issue is that just like with Autism, there's no guaranteed process that's most effective in treating the disorder, just a variety of methods that may be effect how an individual thinks or acts. This is because the personality disorder tends to make a person blind to their own faults or make them not want to change. However, the earlier in life the better and more effective that these therapies tend to be. Yaguichi I think has expressed some desire to change, and I think would be more receptive to therapy as he hasn't depicted the stereotypical narcissism ASPD possesses as much as a sort of egocentrism that has made it hard for him to understand others. He's aware of his own faults and fallibility which indicates he can change and isn't a completely lost cause.
Finally, the issue is that you can't just throw people in jail for having an illness they don't have any control over. It's inhumane and people have legal rights. No matter how horrible the person is, if they haven't broken the law in any provable way they can't be sent to jail as it is a violation of their most basic freedoms and rights. It does matter how gilded or golden the prison cell is, you're still removing an individuals freedom of movement, choice, and association without their consent based entirely on factors they can not control and thought processes, which is dystopian at the most base level. (Also, I find it ironic you've named yourself after the God Emperor of Mankind from 40k, considering I'd argue he definitely also shows signs of Narcissism and Anti Social Personality Disorder himself, especially in the Last Church and throughout the Horus Heresy.)
@TheGodEmperor
I pretty much agree with both your comments, which is why I think he needs treatment because I think he knows something is wrong with him and wants to change, but isn't sure how or isn't completely sure what precisely is wrong with him, and so is kinda caught in a dilemma that he can't fix.
Honestly, he's one of the most interesting characters in the manga so far because of it and I'd like to see where he goes.
@Simply_Fiction