Humans are hardwired to dismiss facts that don’t fit their worldview

In this sense, I think human nature is something to be compensated for. Since people seldom have the presence of mind to do so, it is necessary to impose external controls.

Absent objective morality as Mediochre postulates, why would it be necessary to impose external controls? To allow men to be controlled by their animal instincts is just as good as the opposite, and if we are inherently only self interested, then it may be in our self interest to increase the ignorance of our fellow man towards their 'higher' instincts.