Of course people are going to ignore it if there's no force behind it.
The job interview for doctors is a 5-7 year residency under tight supervision of an attending physician: https://en.wikipedia.org/wiki/Residency_(medicine) . People do flunk or drop out as well, meaning they can never become a physician. There's nothing easier about that.
But I would argue it is way easier there. Building software has way more grey areas.
What grey areas are there for doctors?
It is however just that very small minority of the population with highly psychopathic/narcissistic traits - those that, in pre-historic times, would have been kicked out swiftly of hunter & gatherer / small village communities because of their parasitic nature - that in bigger civilisations seem to thrive due to abstraction (distance/time of the effect of their actions) and obfuscation (PR) and instead unfortunately seem to rise to the top (CEOs, presidents, 'thought leaders' ...) to steer the world's overall economy and mindset - and steer it in the abyss.
Sometimes I think humanity was just not made to scale, and this aspect is one very large aspect of it.
Most likely the same kind of Machiavellian political maneuvering was effective in those groups as well.
The critical point is that the violators have to be punished more consistently then the demanded consistency of the ideals.