There's no way to know for sure, but I am going off of what is being said in Russian news and what Russian officials are saying. I believe Russia is certainly showing more forbearance than the US, at any rate, and I'm glad someone is!
As for serving as a deterrent, that may be true as well. US articles make it sound like our ships are about to start firing on each other and that alone is enough to cause some Americans to oppose the airstrikes in Syria, regardless of whether it is true.