Don't get me wrong here, but I don't think what you (perhaps sarcastically?) state here is a good idea.

If all adults agree to build mechanized genocidal murder factories that will remain a stain on humanity for centuries it is still wrong to do so.

Some rights are non-negotiable to my eyes. Even (or maybe especially) when a democratic majority decides to break them. Legality doesn't matter here. The concentration camps next to where I grew up were also legal during Nazi reign. That doesn't make them right, not back then, not now and not in the future.

I'd highly advise against a petty "let's se where that gets them"-stance when it comes to human rights issues, because those paying the price are not those who commit the atrocities.