When I ask any person anywhere on this planet: what should happen to serial killers and child predators? No matter where I go I get the same answer.

Kill and/or torture them, I suppose? I also get annoyed by on the road sometimes.

The law is a joke and protects only those in power.

I think this very much depends on where you live. To an extent this is always true as there is always some abuse of power. Where I live, the laws and executive branch protect those with and without power depending on the circumstance. Regardless, I don't really see how this is particulary relevant here.

Countries and societies that will prevail in the next 1000 years do their shit still the old school way: Eye for an eye.

Eye for an eye, or tit for tat, is a relatively good strategy from a game-theoretical perspective (depending on the setting). However, violent criminals are not typically acting rationally in their best self-interest anyway. I think retributive violence can have both stabilizing and destabilizing effects on factors like social cohesion and trust, depending on local culture.

For some sins there is no excuse,

Guilt and responsibility are useful abstractions/regulators in daily life, but talking about criminal justice on a societal scale, they become nonsensical. "Excuses" are only meaningful in the context of assuming freeedom of choice, like a criminal could have chosen not to perform their crime. Of course, this is not true, as decisions are physical processes, which are deterministic at the scale of the brain (or even if random, they are not influenced by some homonculus of 'self'). Violent criminals cannot help that their brains are fucked, and they could not have decided not to perform their crime. Unfortunately for them that means that until we have a cure for that, they have to be separated from society until deemed sufficiently safe (which is a political decision). Or society decides to kill them; whatever. In any case, excuses are irrelevant.

No rehabilitation can undo their deeds.

Of course not. Although I think this implies retributive justice.

I don't give a fuck why they did it, it's irrelevant.

If your goal is to prevent such crimes from re-occuring, it is quite relevant (not necessarily their own explanations, but what we can eventually find out about the causal chain preceeding these behaviors).

In what society do you want to live in?

Ideally, one where people understand that what is typically called free will obviously does not exist. One where neurophysiology is understood to such extent that we can prevent pedophilia or violent crime from occurring in the first place; wherein we can prevent brains from developing such degree of psychopathy (at least if that can be accomplished without even more of a draconian authoritarian surveillance), and where we can cure criminals from before those times.

More realistically (at least in the short-term), one where retributive justice / punishing humans for sake of punishment is seen as ridiculous as punishing a car for an engine malfunction, instead of trying to repair it. But that is just my view.

And do you think our "civilized" model will stand the test of time?

I think we will most likely destroy ourselves with nukes, bioweapons, or yet to be discovered technology. But if not, I think our "civilized" model will become irrelevant by the time we can redesigned our hardware not to be so crappy anymore.

What do you think? Do you think my take is retarded? Feel free to say so, of course.