They absolutely prevented aid from flowing. There's a single crossing where merchandise is allowed, and it's in Israel. Egypt is not allowed to let merchandise in , and that's since the camp David treaty back in the 70s. Way before Gaza became an insurgent nest. The west bank was the hotspot back then but it didn't prevent Israel from preventing any development there, and occupying the place until 2005.

Also, for a concrete example, you can look at the Gaza flotilla attack where Israel not only prevented aid, but literally murdered those on the ship. Just like the Houthis do, I guess :). Again, how can Israel claim that they have left Gaza alone when it is literally completely cutting it off from the outside world (again, the Gaza residents are at the mercy of whatever goes through Israel before Hamas took control). Hamas is a convenient boogeyman, but before Hamas Israel settlements already existed, Israeli occupation and complete control over external connections was already in place, etc.

Israel does not leave the west bank alone either now, even with no real armed groups left there.