At best you can compare the average rainfall to the driest southeasternmost part of England. However, in the West Bank the rain doesn't fall the way it does in England. It falls more irregularly, sometimes causing flash floods like last November. Also, the temperature is higher, whatever rain falls it also dries up quick. West Bank depends on cisterns and irrigation, which aren't really a thing in England. So yes, while technically not all of Israel and Palestine is a desert, most of it is, and even the parts that are technically not deserts are very vulnerable, and will become uninhabitable in a few decades.