Earlier quoted context omitted.
That's cheating. A person is only a homicidal psychopath after they have committed homicide. Locking up a psychopath who has committed no crimes is just as fucked up as locking up someone for being gay.
Whether we lock them up or punish them afterwards is besides the point: in either case the "I'm genetically programmed this way" is not a defense that would (or should) fly when it comes to murder.
There may be individuals biologically inclined to commit murder, but they still don't have to. Gay people have no autonomy at all in choosing their sexual orientation. Even if you had a direct mandate from god that engaging in homosexual behavior was immoral, it would be unethical to punish someone for the way they were born. Punishing psychopaths for murdering people might have a weak argument against it, but it still seems reasonable under most legal/civic/ethical frameworks.