They are upset that the sites are being called "Jewish heritage sites."
From Palestine Press Agency:
The city of Hebron in the West Bank called a strike this morning in response to the call by Fatah to protest the Israeli decision to annex the Ibrahimi Mosque and another mosque of the heritage sites of Judaism.Palestine Today:
The strike affected all walks of life in the city of Hebron, including schools and universities, as the are protesting the decision of the Israeli Prime Minister to include the Ibrahimi Mosque and the Mosque of Bilal to the list of heritage sites of Judaism.
Clashes are continuing clashes between Palestinian youths and Israeli occupation forces in the vicinity of the Ibrahimi Mosque in Hebron in the West Bank, to condemned the Israeli government's decision to annex the Ibrahimi Mosque as a Jewish religious site.
Also Palestine Today:
Sheikh Kamal Khatib, deputy head of the northern wing of the Islamic Movement of Palestine occupied in 1948, warned that the declaration of Israel on Sunday night to include the Ibrahimi Mosque in Hebron to the list of so-called Jewish heritage sites is only a "rehearsal" to see the reaction from Muslims as they plan to Judaize the Al Aqsa Mosque in the middle of next month.
The secular Al Quds:
The Israeli government had decided at the weekend, the restoration of its landmark of 150 historic Jewish sites, as "sites of special heritage status," and carry out development of the expanded and transformed into tourist sites. Among these sites the Ibrahimi Mosque in Hebron and Rachel's Tomb (near Bilal Ben Rabah mosque) in Bethlehem, outside the city walls of Jerusalem.(It is interesting that Al Quds says that Rachel's Tomb is "near" the Bilal mosque, not in the same place, as Palestinian Arabs have been claiming for the past decade or so.)
These riots have nothing to do with Israel and everything to do with Jews asserting their rights to their holiest sites.
Even while the "hawkish," "extremist," "right-wing" government of Binyomin Netanyahu takes pains to emphasize that in no way is he interested in diminishing Muslim rights to their holy places, the Palestinian Arabs - even the supposedly secular ones - are trying mightily to keep all Jews out of every one of their alleged holy places, which, not coincidentally, are all belatedly considered Muslim holy places as well.
Every conciliatory move that Israel has done towards accommodation is taken as proof that Jews aren't as attached to their holy places as Muslims are, and it emboldens the Arabs more and more.
The harsh reality is that if Israel would have annexed these sites in 1967 - including the Temple Mount - the Arabs would have grumbled but they would have understood and respected it. They project their own attitudes towards the Jews and expect them to act the way they would have. Only when the government of the Jewish state wavers as to how important these sites are do the problems arise.
And keep in mind that the Muslims claim the Western Wall as well, so if Israel caves on this, it won't help "peace" - it will just move the battle towards Jerusalem.