Because they didn't respond a year ago to cruise missile attack other than wild claims about how many they shot down?
Russian families are trying to get their government to admit to the casualties, they haven't been hearing from their relatives in Syria.
A cover up isn't exactly a violent response.
“Because they didn’t respond a year ago to cruise missile attack other than wild claims about how many they shot down?”
Ok, that’s a good reason to start WW3. Right.