The UN has passed 3 separate resolutions (in 1978, 2004, and 2006), telling Lebanon to get all non-state militias out of the south, and away from Israel.
Lebanon had decades to stop these armies from attacking Israel from within their borders.
They chose not to act.
So, Israel is doing what any Western nation would have done decades ago.
I'm not even a fan, but this seems like bad stewardship. It really feels like they've stopped trying.