For whatever reason, maybe in the past, I recall Israel demanding the total disassembly of groups like Hamas, not just disarming them. Clearly this isn't the case now.

Still, to address groups like Hamas, Fatah (or another centrist/secularist group) needs to get back to the grassroots, clean up the corruption at the top, and gain the trust of the people. The worst case scenario of Likud running Israel and Hamas in charge of the Authority is looking more likely everyday.