You’re mixing up things. Proportionality is a specific thing about scale. It doesn’t say you’re not allowed to respond to failed attacks.

You can for example evaluate the likely future harm your enemy would cause if you don’t stop them and then apply the proportionality principle to that when you try to stop them. Or evaluate likely harm if somebody else attempted and succeeded with an attack you just stopped, and decide what kind of deterrence is needed based on that.

And Israel isn’t just doing a shit job of it. they’re not doing it at all