::::::"Meets the definition of" and "is a neutral description of" are completely different things.  Basically every attack in Category:Attacks in 2014 meets the definition of massacre, yet are not titled as such.  Why? Because reliable sources do not consistantly use the term to describe the event, just as is the case here.  Quality news sources understand massacre is a loaded term and are very hestitant to use it.  If you don't understand it is a loaded term, then in your dialect of English perhaps it is not, but in most dialects it is. 
 ::::::The norm for such articles is to use the term "attack"; the vast majority of reliable sources use "attack"; the article's original title was "attack".  The burden of proof this should be called otherwise is on you.  Merely stating it meets the definition of massacre is insufficient.  It certainly meets the defition of an attack too! 
 ::::::BTW, even the recent events linked from List of events named massacres are in fact not titled "X massacre" on Wikipedia.  Most likely the 1/22 events in:Category:Attacks in 2014 titled massacre should not be either.