What does this change?
Not much, except to remove the facade of peaceful intentions that the PLO had hoodwinked the world into believing.
Believing after the inherently flawed Oslo agreement, inherently flawed that Yasser Arafat's PLO (renamed the PA) never genuinely reconciled itself to peaceful coexistence with Israel or renounced violence as a political tool.
So, in the end, Hamas's overtly rejectionist and violent stance against Israel's right to exist merely makes the pre-existing Palestinian Arab policy formal and open. No more second-guessing for the peace-minded weak. There established policy will be the policy they belive in.