I am not sure who do you mean by usurpers. Here is the colonisers association, tasked with creating colonies: https://en.m.wikipedia.org/wiki/Jewish_Colonisation_Associat...

The colony in Palestine took off, due to the British preference of solidifying european control over Ottoman region, and the convenient façade of the historical claim.

People lived there before this are descendents of those who lived there in the past. Many stayed even after the expulsion by Romans, many returned. Some, obviously would have changed their faith, but none of that gives the European descendents any more right over it. We can all colonise Ethiopia if we were to go on like this.