Legally, Haram al Sharif was part of the territories that Israel seized in the 1967 war. For Jews, the Western Wall has been, in effect, an open synagogue, where Jews prayed and remembered the Second Temple. Although the Western Wall was under Jordanian control until 1967, Arafat agreed that it would remain under Israeli sovereignty. Making matters difficult for Barak's case was the Israeli opening position on Jerusalem, which called for separating political from religious aspects. But these were taboo issues for much of the peace camp, in the same way that the contemplation of anything less than Palestinian sovereignty seemed taboo to Arafat.
Blame is always easier than looking deep inside.
This frustration is bolstered by unfortunate statements made by Arafat's aides about the utility of violence for negotiations. This is made worse if one assumes, as some in the peace camp did, that Arafat could have given more on Jerusalem but was supporting violence to extract unreasonable concessions. Suppose he felt that the U.S. and Israel were maneuvering to demonstrate that he is weak and had no option but to accept what he knew he couldn't. This scenario would put his moves in a different light, not too different from Barak's moves. Barak, for example, also used force strategically.