I guess that they generally travel after finishing their 2 or 3 years (for officers) in the army, and having undergone such a strict military lifestyle, they just want to let their feelings out and be free.. . As many of them often travel to similar destinations, e.g. Thailand, India, Nepal, Bolivia, Peru..., they tend to form large groups and do whatever they feel is fun.. . Mind you, I have many good backpacking friends who are Israelis, but they tend to prefer to travel alone or with their partners and not with a big group of crazy Israelis.