"Artillery of Hell" in the Syrian war

Do you know that neither Amnesty International nor Human Rights Watch have taken a stance against the use of "artillery of hell" used by Syrian rebels (where a gas cylinder is used as a shell)?  Both barrel bombs AND artillery of hell should be condemned.  Also, how come neither Amnesty International nor Human Rights Watch condemned the Lebanese Army back in 2007 when it used barrel bombs against the defenseless Nahr Al-Barid refugee camp?