Ignoring the "Anglosaxon" buzzword here, none of this is unique conceptually to US law, or foreign conceptually to anyone who's told a lie when younger. It's instinctual for many when they know they've done something wrong. Trying to paint human nature as a unique problem that US law faces, or promotes, is itself dishonest.
> claim incompetence or mental incapacity
Neither of these get you "off the hook"; that's a misconception.
> That's how you end up with people who are total experts in their field testifying in courts that they "didnt know" that something they did would cause so much harm to something or somebody or the society.
It can be either dishonesty, or lack of omniscience by the expert in question. Unless you're a mind reader, you have no idea. This is why testimony is evaluated along with other aspects of a case, and not alone.
> There wont be any trail of their wrongdoing, and when there is, there will always be plausible deniability in that trail...
Plausible deniability does not shield you from all liability.