The use of the word "just" is no accident. It means that unless Israel allows itself to be flooded with millions of angry, antisemitic Arabs, destroying the Jewish state, there is no "justice."
"Justice" has long been a keyword of the anti-Israel crowd. It is effective because who is against justice? What it really means is that the stateless Arabs are the judge and jury to determine what is "just." UNRWA's webpage even asks lots of Palestinian Arabs what they think would be "just." People who live in the territories say they want to live in their grandparents' homes in "their country," and only that would be "just."
The mandate that created UNRWA said that it had two goals:
7. Establishes the United Nations Relief and Works Agency for Palestine Refugees in the Near East:That was originally meant to be 6 months, not 65 years.
(a) To carry out in collaboration with local governments the direct relief and works programmes as recommended by the Economic Survey Mission;
(b) To consult with the interested Near Eastern Governments concerning measures to be taken by them preparatory to the time when international assistance for relief and works projects is no longer available;
But the Arab governments didn't cooperate. They didn't want to assimilate the Palestinian Arabs into their countries. UNRWA kept trying, for several years, to reduce the refugee population, and then in the face of Arab national intransigence they gave up.
And now they only blame Israel.
There is nothing just about the idea of a "Just Solution." It is not meant to solve any problem (as can be seen by the continued existence of UNRWA camps in areas fully governed by the PA and Hamas.) The entire campaign is designed to destroy the Jewish state demographically under the imprimatur of "justice."
Notice that UNRWA didn't start this campaign on its own anniversary. It started it on the anniversary of Israel's declaring independence.
That says volumes.
Previous essay on how anti-Israel activists misuse the word "justice" here.