The young child knows that the world is created, and by a creator - the child spontaneously goes-along with this, unconsciously, without a choice...
Injustice is the violation of divine intent as manifested in creation - to be unjust is to reject the intent behind creation.
Then, often, the idea of the world as created comes to awareness - and is rejected (once known it can be rejected). The world is reconceptualised as accidental, something that just is...
This is an act of freedom, an ultimate and isolated act of freedom - the freedom to be existentially cut-off; so as not to be subject to creation and the intent of the creator.
The sense of justice is not eradicated - but justice lacks any basis. One it has been asserted that there is no reason to reality, there can be no justice...
Yet the demand for justice cannot be expunged - the cry of 'it's not fair' sounds throughout history, among people of all ages and cultures; and is as common (or more so) among those who reject the reality of creation and of God, and among those who oppose the purpose of creation.
The self just-is autonomous from the rest of reality, not wholly but to an inextinguishable degree. From this fortress Man asserts his inaleinable right to reject an alliance with creation - but Man does not enjoy being utterly alone, utterly cut-off from any possibility of meaning, purpose and relationship.
The autonomous self screams that It Is Not Fair - His cut-off freedom, and isolated Justice demand that the world be subordinated to himself; who did not create it, but who will not acknowledge either that it was created or will not agree with the purposes and meanings and relations made manifest by the creator.
He sets-up as a rival God, and tries to recruit followers who will acknowledge his own status - but an anti-God whose 'good news' consists in the fact that 'You-too (like me) can rejects creation and the creator; you-too (like me) can hold out against the deity that made everything Good.
The final act of Justice as it dwindles toward nothing, is to cry against the injustice of having-to be a part of pre-existent, other-made creation if we want real justice: rejection of that compulsion is that last and decisive act.
Freedom-in-autonomy asserted above and against everything else.
To become an anti-God of this sort (and in this kind of way) is not an exceptional nor unusual achievement achievement. It is not even rare - but perhaps mainstream in the modern West (at least apparently-so): This is a society of would-be anti-Gods, each aspiring to usurp creation under his own sovereignty, and ultimately and inevitably failing to do so because everybody wants to be his own anti-God and to reject the overlordship of all other anti-Gods.
Meanwhile, the anti-Gods form a loose and mutually-hostile alliance to make more anti-Gods, each of them presumably in hope of enlarging the pool of potential recruits for their own attempted takeover of creation.
Hence the insistent cry for justice, and the anger at injustice - anger at the base-injustice that autonomous freedom in a meaningless reality would, if achieved, be an eternity of meaninglessness.