I could say the same. Especially when you still dive into baiting a la "It often happens when one is short of arguments." Uh-huh. That determined to derail the talk into your nonsense, huh?
Well, first of all, since you posted a bunch of postulates, it's up to you to have an argument to support them. Speculating about whether I have a counter-argument or not, is cute in its idiocy, but it's still your burden of proof not mine.
That said, problem still is: it is a complete red herring. It has nothing to do with determinism. The whole argument is completely and utterly orthogonal to it. To wit:
1. The retarded are still exactly as retarded, and just as incurable of it, regardless of whether you hypothesize their brains to function deterministically or not.
2. Exactly how productive members of society they are, is also the same, regardless of whether you hypothesize their brains to function deterministically or not.
3. The costs of caring for them are still the exact same, regardless of whether you consider their brains to function deterministically or not.
4. The chances of passing it on to offspring (since really Hitler's reason was eugenics, not philosophy of the mind) are still the exact same, regardless of whether you consider their brains to function deterministically or not.
5. Whether the state needs to care for its citizens, and how much, is also rather independent of whether you believe in determinism or not.
6. The supposed burden to the state needs to be first demonstrated, not just pulled out of the ass and proclaimed to be beyond questioning. You are not the pope, you don't get to do infallible pronouncements. There are plenty of menial jobs that can be done perfectly well by people with mild or even moderate retardation. Which is to say, IQ 35 or higher. Which covers the VAST majority of people with intellectual deficiency.
But also because:
7. How well a country functions is also dependent on cultural and sociological factors. National unity, morale, etc, are actually very important. It does not follow that starting killing people's relatives is actually better for the country, even if it saves a few bucks in the short term. You have to support that idea, not just postulate that it's unquestionable, silly.
8. "If you are determinist the word “persuade” has not many sense. There are caused behaviours." That is at best a dumb word game, and at worst downright stupid. Persuasion is one way to cause a desired behaviour. The idea that if someone believes in deterministic decision making, they'd necessarily become oblivious to half the data that goes into making those decision, is just plain old nonsense.
9. "If you can modify a behaviour changing its causes, you do it. If you cannot do it, you can eliminate the problem. This is to say, eliminating retarded persons. The final solution, you know." Again, that's downright stupid. It postulates motivations and goals which are not part of just believing in deterministic decision making. Just believing that something works in a certain way, doesn't automatically involve wanting to solve EVERYTHING even vaguely related to it.
10. It also postulates a kind of black and white thinking that is not a given. Even if one believes that certain decisions are deterministic, it doesn't follow that they'd necessarily then classify every single decision into either perfect or deserving nothing short of death. It doesn't follow that basically if you think that thought processes are deterministic, you'd automatically believe in the Nirvana Fallacy. It's a fallacy for a reason. And known to be one.
If you want to postulate that such thinking is inherent, then support it. Or don't. But in the meantime, poisoning-the-well rhetoric about how everyone who's of a different school of philosophy than you is nothing short of a proponent of a "final solution" is itself idiotic.
Not the least because:
11. Even where punishments are involved, there is a benefit from having a more gradual scale. And I've already repeatedly given a reason why. The notion that if someone believes that there's a deterministic cause-effect at work, they'd automatically be unable to comprehend that certain causes work better towards producing an effect, is not a given.
12. "Or you punish them in a so awful way than other possible evildoers are dissuaded." Again, that's postulating that more awful punishments work better. That is not a given. Support it, or don't, but just repeating it like a broken record doesn't at some point just make it true.
But more importantly:
13. That returns in a circle to your implying that being retarded equals being an evildoer. If that seems in any way obvious a premise to you, then the problem is in YOUR mental model, and you can stop projecting. It does not follow that if one believes in deterministic decision making, they'd automatically be oblivious to 2500 years or so of figuring out the best justice system.
E.g., that they'd totally forget fundamental principles like needing a Mens Rea (evil intent) before something qualifies as evildoing, or why those principles are there. In fact, just that one alone automatically excludes anything out of your control from being qualified as evildoing. Unless someone actually wanted to be retarded and made themselves so, it CAN'T qualify as evildoing.
Even more importantly:
14. Again, there you try to sneak in the downright idiotic notion that any "deterrence" can even be conceived when it comes to something like being retarded. You can escalate punishment as high as you wish, it still CAN'T deter someone from being retarded. Again, you just postulate that someone who's a believer in deterministic decision making, would be automatically oblivious to that, and try to apply the same to everything whether it can actually be deterred or not. That is not a given.
Etc.
But basically, as I've said it the first time: "Your whole post is by now just a hodge-podge of bare postulates about what someone else thinks, what is best for society, etc, without any support other than that you said so." Speculating about my possible reasons and reactions to it doesn't change the fact that it's YOUR burden of proof to support all that.