This is really stupid. People love to simplify things that can't be simplified especially when we are talking about a conflict so old and so complicated like the Arab-Israeli conflict. To those Arab protesters, it's not just about stupid metal detectors.. the core of the issue is a fight over control and ownership of sacred religious sites. East Jerusalem belongs to the Arabs. So when Israelis, without even consulting with Palestinian leaders, decide to place metal detectors and impose unusually strict security measures on access to the Temple Mount area, even go as far as banning any Palestinian men under the age of 50 from Friday prayers, what would they expect to happen? This is east Jerusalem we are talking about, the Arabs part of the city.
Even some of the Israeli news papers are questioning Netanyahu's exterme measures, saying that it could've been handled delicately if Palestinian leaders were involved and Arabs had a say in it. But no, let's just simplify things. it's much easier that way.