They are religious extremists who believe that the entire land should be free of anyone whose religious beliefs do not match theirs and they don't mind killing innocent people, including their own people- women, children, etc. to further that goal.

The fact that some countries such as Russia and Turkey won't label them as terrorists doesn't change their beliefs, nor does it change how dangerous they are not only to Israel, but to their own people. They take the "long view" that if they need to sacrifice a few dozen, hundred or thousand of their own people to achieve their goal, even if it takes centuries, they're willing to do that.

It hurts not only Israel, but the people of the Gaza strip as well.

I don't want to split hairs about who calls labels them what. As I said, my explanation is simplified.