The old lesson. Where a citizen cedes a monopoly on violence - including self-defense - to the State in order to create a "peaceful" society, he trusts the State to employ it in his protection. This may be withheld if the State has priorities other than the protection of the citizen. "Social justice" is one of those priorities, but it can be anything - once in Germany it was racial purification.
When that protection is withheld the citizen is helpless. The right of self-defense must never be ceded to the State.