It's pretty simple - tell me why you think it's justified for Lebanon to attack Israel?

You're dancing around the "context" but not actually saying why that context makes it legitimate for Lebanon to attack based on the pre Oct 7th status quo. Sure Lebanon and Israel have some territorial dispute, but it's like 20 sq km, not something you should start a war for.

Lots of neighboring countries have a bloody history, that doesn't mean starting a new war is legitimate, right? Can Poland start firing rockets at Germany because Germany invaded them in the past?