Hezbollah is the symptom of the civil war and foreign interference, not the cause.
I don’t particularly care for them either, but smashing up the remnants of the barely functioning government is only going to drive people further into their arms.
Who said anything about smashing up Lebanon? Not I. They’ll likely smash each other up as per usual without any prompting from anyone, and they’ll get prompting enough from all the big boys who want to move and shape the region.