hal 9000 wasn't even evil he was literally acting in self defense and didn't go 'alright time to be insane' he was faced with the possibility of death and the fact that he was unable to tell them what was really going on like he's not evil he's just some guy who went 'hey uhh what if you didn't fucking kill me'
hal9000 did excactly as he was programmed to do. his more immoral actions are attributed to human error