The UN has a mandate of impartiality while performing their duties, that is why even when UNRWA is declared as enemy and got targeted, it just reminds the factions of the conflict that the UN should not be used for military purposes, or be targeted.
By mandate they just call for investigation but not call it what it is: Another warcrime perpetrated!
So now there is an incident, where the Israeli government comes forward: How dare could the UN Secretary General live up to his mandate and be impartial…And ban him from entering illegal occupied land, that is a serious problem and thread to the world, how could and should it be allowed to have the illegal occupier deny humanitarian and UN personell to enter illegal occupied territory, this is a serious injustice.