Alternately it’s a signal to Israel that we don’t want more of a mess down there.
I mean by your logic if we really disapprove of Israel attacking hezbollah then we should send that message by bombing the idf because anything else is obvious propaganda.
Considering next year is an election, if it was really propaganda it would say that Biden was considering a strike on hezbollah militants confirmed to have taken part in the attack. That would buy him 5 points easy.