Perhaps it's a simple misunderstanding around terminology. I certainly wouldn't say that Britain at the height of empire was a "settler colony". I would reserve that description for the colonies themselves, i.e. those settlements outside Britain itself! Likewise I wouldn't describe Israel as a "settler colony" simply because it has (perceived) colonies outside its borders. I would only say that if I believe that Israel had no right to exist within any borders. But perhaps that's not what you meant and I just misunderstood you.