As yo ualrady addmitted in your post Mexico and USA have joined forces in the fight against the drug cartells and they are fighting this form of terrorism hand in hand. If Lebanon would do the same with Israel then tehy would not be held responsible. So far Lebanon is not working together with Israel in fighting teh Hezbollah terror. Actually Lebanon does not have to cooperate with Israel in order to avoid responsibility however they must be able to fight it effectively. If they are not effective then they are not fullfilling their responsiblity.
One student killed, three wounded at Arizona campus during fight (a)
from the article: Lebanon army dismantles 4 rockets aimed at Israel