Hamas at least is not selling the Palestinians out. And they're not keeping any agreements from happening, either. They have said that if the Palestinian people voted in a referendum to accept a two state solution and to recognize Israel, they, Hamas, would not stand in the way of it.

The people who are keeping agreements from happening are the ones who are trying to get the Palestinians to agree to things that they would not agree to themselves if they were in the Palestinians' shoes (that would be the governments of Israel and the US).