What you propose:

"Terrorists might've done something good actually. In some foreseeable future we might see changes in the world that would actually benefit them in the result, making their terrorism not useless"

What I propose:

"No human can see the future. But hamas could perfectly see what would happen if they launched such a violent attack - invasion with the purpose of removing hamas as an entity. If I can't blame them for not surrendering by now, I will blame them for not making anything to defend their citizens."