let me ask your question with an other question: How many lives can a spy agency kill until it is no longer acceptable?
So let say the French intelligence service decide to plant one on a nuclear power plan in the US. Sadly however it has a bug which goes off and partial shuts down the reactor. A meltdown happens, killing a few thousands and irradiate the surroundings.
Do you go to war over this? Would you classify it as an attack, a accident, or a act of war?
Lets assume that radio and TV inside Syria informed the public where current fire fights happened, where people should go to seek shelter, and other warnings of dangers to the civilian population. Radio and TV get this information from sources inside government and reporters on the field, some using The Internet to transmit this information.
You cut that communication line and radio and TV do not have current information to broadcast. People dies as a result. A lot of innocent civilians dies. This singular event could have killed more people than horrific event like 9/11 or a meltdown at a power plant.
This is why I ask: How many casualties is a spy agency allowed to inflict until it is no longer acceptable.