Propaganda isn't needed to show that Assad needs to be removed.
Syria supports Hizbollah in Lebanon. They give safe haven and protection to Hizbollah in Syria.Hizbollah is responsible for killing our marines back in 1983. Shall I go on?
Syria also provides safehaven and material support for HAMAS, the Abu Musa Organization, Palestinian Islamic Jihad, the Popular Front for the Liberation of Palestine General Command and the Popular Front for the Liberation of Palestine... Shall I go on?
Syria is a state sponsor of terrorism -- no propaganda needed.