The only thing about trying to rehabilitate Lore with "psychiatric/technological" is that he's too smart for the psychiatrists/therapists and could fool them; second, he and Data are nearly identical except for some bits of programming which have been implied to be Data's inability to use contractions, lack of emotions and non human like behavior. Their identical programming could included the self correcting mechanism Geordi mentioned in Contagion. That bit of programming could undo any type of technological "cures" used on him. Shutting him off seems the most human and safest way to deal with Lore.
Perhaps, in the future, another cyberneticist could have the chance to study the deactivated Lore, maybe even B-4, and find a way to purge the homicidal/genocidal tendencies from him and reprogram the self correcting mechanism to the newly designed programming, thereby rehabilitating him.