Israel has attacked Lebanon in part because under international law such a response is legally justified. We are hearing about " proportionality" only because Israel is so clearly within its rights to respond militarily to Hezbollah that the case for Israeli "aggression", which would be the normal diplomatic response, cannot pass the laugh test.

Morally, Israel would be far better off having attacked Syria, a primary backer of Hezbollah but this would be an act of aggression and illegal as Syria's aid is technically covert and more deniable. You can't deny Hezbollah's geographic location in quite the same fashion.

I'm not sure of the extent to which the IDF plans its operational strategy with the aid of lawyers but it sure looks like the consultation was considerable.