If someone is mentally ill you want to kill them?
If they are mentally ill you lock them up and try treating them if they are a risk to the public.
You are meant to read an entire post you know, not just selectively read bits that you want.
I didn't say we should go around killing the mentally ill, I said those that pose a threat. I have family that have mental disabilities: one of my cousins is autistic, my uncle has epilepsy and because he developed it early and had fits from the age of 3 upwards, it damaged his brain so he can't speak, can only just walk, doesn't have complete motor coordination etc, I don't think they should be killed, they aren't a threat to anyone.
If you get someone with a mental illness though, going around smuggling drugs, abusing people, murdering, any extreme crime, they deserve it as much as a sane person. The death penalty is there to protect innocent people from those that pose an extreme threat, and someone that is soud in mind that is a murderer or drug traficer is as much of a risk as someone with a mental illness doing the same, and so should be treated the same.
It is all well and good saying rehabilitate them, but they go and harm others, it isn't worth it for one person to get a bit better, them affecting peoples lives directly or indirectly.