Israel is a legally constituted sovereign nation under constant attack by those who openly declare their intention to eliminate it and if necessary to annihilate the population.  That Israel takes harsh and often preemptive measures against these things is understandable and perfectly moral and legal.  While sometimes its measures may in even my opinion be counterproductive and regrettable, they should not be second-guessed by arm-chair types sitting comfortably at home and not under regular bombardment and terrorist attack.   The propaganda that distorts this ongoing reality should be simply dismissed.  The Palestinians have had many chances for peace and will not accept them.  That is their decision and they have to live with the world they have created.