Bill Maher was talking about ISIS on his show a few weeks ago about how basically the borders in the middle east were all drawn a century or so ago by western powers without any regard for the peoples who populated those regions beforehand, and we're just seeing the ramifications of that play out. I think he's right.
But we have to remember that we ALSO arbitrarily drew the lines for Israel and it's reasonable to consider it just as illegitimate.
I'm no fan of ISIS or Hamas or AQ, but all this chaos is just the emergence of a millenia old religious conflict between Sunni and Shia, exacerbated by ignorant meddling. There will be no resolution until we stop interfering, and that interference includes the blind backing of Israel.
We should wash our hands of it once and for all and wait for the dust to clear.