Why have Arab governments forbidden Palestinians from leaving their refugee camps and becoming active members and citizens of those other Arab States?

Answer 1

If Arab governments permitted Palestinians to become citizens of their states, it would offer a viable solution to the Israeli-Palestinian Conflict especially where refugees are concerned. This would help to legitimize Israel, which is something that the Arab States prefer to avoid. Therefore they allow these refugees and their descendents to suffer needlessly to strengthen their political ploy that Israel needs to go.

Unfortunately, Arabs are not critical of this particular government action which expresses inhumanity to their own Arab brethren and prefer to tow the government line and blame Israel for a pitiable situation for which it is not responsible. (This is not to say that Israel does not have concessions to make with regards to Palestine, only that the situation of Palestinians in Arab countries is not within Israel's control.)