During the many times the Arab League declared war. They lost though, which is why they’ve been limited to Gaza and West bank.
But more importantly, this genocide is not a two way street. There are terrorist attacks but that pales in comparison to an all out genocide. When have Palestinians leveled whole neighborhoods or dropped chemical weapons on people? Israelis are determined to kill or at least displace the millions of remaining Palestinians and it’s disingenuous to say that’s the same thing the Palestinians are doing.
It very much is. The situation in Palestine and Israel has always been very back and forth, with terrorist attacks from both sides, military strikes into each other’s territories, the deaths of innocent civilians, such and such. No one is a saint here, except for those caught in the crossfire.