What was Assads motivation for using them last year?
What was Assads motivation for trying to build a nuclear plant?
What is Assads motivation for letting Hammas attack Israel from his country?
The answer is the same for all of these, and the response from the outside is the same for all of these. Does aside seem like a rationale person to you?
You are assuming that Assad did it last year too. That may be true, but what is the evidence?
Does aside [sic] seem like a rationale person to you?
If you get your way and Assad is removed, I think it's likely that whatever Syria becomes as a result will be a lot less "rational." But that will make the deep state happy. Under Assad, Christians and other groups have survived.