Every democracy that I'm aware of has on its books that sort of crime when the organization is engaged in criminal behaviour. In that event, directing minds of the organization, whether it is a corporation or criminal gang, are subject to criminal sanction. Of course, this situation is unique. But in principal there is nothing wrong with going after the directing minds of an organization that has targeted and continues to target civilians. As to occupation (a) there is none in Gaza & (b) the history of the occupation of the West Bank demonstrates irrefutably that it is the fault of the Pals and their Arab allies (c) it lies ill in the mouth of occupiers, Pals and there Arab allies to complain about occupiers who were the original peoples turfed from lands (and those that were turfed were the lucky ones) & (d) the Jordanians abandoned those lands and in that event the first national entity to occupy gets the lands. Having said all of that, Pal people do deserve a place where they feel safe and secure and not subject to the vagaries of other countries. But not if they operate as violent, barbaric terrorists. Then they deserve less than the currently have.
Palestinian reportedly shot dead by Israeli soldiers after approaching Gaza border fence (Haaretz)
from the article: Hamas official detained hours after release from Israeli jail