They don’t believe it. It’s just a talking point to cover for genocide. Nettanyahu, like all the right-wing authoritarian fucksticks before him, is about as attached to his excuses as the Navajo nation is to water polo (spoiler: they’re not). It’s just some bullshit to spout while you fucking murder people. If the excuse runs thin, fuck it, just make a new excuse, but this is the one they’ve spent decades cultivating by literally funding hamas.
Illegal for the people doing and taking the bribe, with real teeth.