A few details make the situation quite different. First would have to be conditions. Israeli prisons are required to adhere to the Geneva convention. They are not very different than North American prisons, possibly even more humane. Hamas regularly tortures it's own citizens. Secondly, Red Cross has access to all palestinians in Israli prisons. They monitor conditions regularly. This is required by international law. Without this condition, they cannot be considered a POW. The Red Cross has been repeatedly refused access to Gilad Shalit, and lodged multiple complaints against Hamas for this infraction. Thirdly, and very importantly, Palestinians who were arrested were arrested with cause and given a trial. Many of them have blood on their hands, in other words they tried or succeded in killing Israeli's, usually civilians. They are still given food, education, and eventual parole. This does not compare to a soldier, in his country, defending his borders. Lastly, and very importantly, many people accuse Israel of Barbarism, brutality, wonton killing. In the last decade or war, less than 10 thousand Palestinians have been killed. Palestine was originally started in Jordan in the 70s. When the King of Jordan refused, he launched an offensive now refered to as Black September. Over 25000 palestininas were killed in a month. Israel does it's best to avoid loss of human life, even moreso than it's arab neighbors, the palestinians cousins.
PLO official: Reports about Abbas' resignation from political life very premature (Haaretz)