James Poniewozik has a good piece on this on his blog at TIME. My favourite part, though he doesn't pick up on it, is that when he queried CNN about their reasoning they said (and actually Nasr herself said):
It was an error of judgment for Octavia Nasr to write such a simplistic tweet about the death of Sayyed Mohammad Hussein Fadlallah.
Such a simplistic tweet? It was a tweet, for God's sake. 140 characters.
Anyway, that's leaving aside the whole problem of firing a journalist for expressing respect for a single newly-deceased leader of Hezbollah. The sooner the world accepts that both Hamas and Hezbollah are political entities that provide social services and back elected members of governments, the sooner they will have the momentum needed to end their violent activities. They, or perhaps more specifically the moderates within those parties, need an incentive to demilitarize. Having vapours every time they are mentioned in a non-terrorist capacity does not facilitate their rehabilitation.