A number of US drone strikes within few days have killed “dozens of suspected militants” of Al Qaeda in Yemen. This is considered as success in the US and is reported as good news in western press:
This is because in Yemen (just as in Afghanistan or Pakistan) Al Qaeda fighters or those with almost identical attitude and methods are considered terrorists. Not however in Syria, where their existence and relevance is either denied or belittled. Thus, it is tolerated by the US, UK, France, Turkey and implicitly also by Israel that the Syrian Nusra Front is non other than the local branch of Al Qaeda and that most supposedly “moderate” rebel groups closely and regularly cooperate with the Nusra.