I think the point of origin is the ultimate defining point of whether it can be called "anime" or not. I also think it's better to say that it's made "in an anime-style" or "a style similar to anime", because aesthetically, that is what they are looking for. Among many examples, is what hapens when you listen to the Star Wars soundtrack, and then listen to Gustav Holst's Planets (try it, I dare you), or a whole lot of other symphonic works. Point is: that soundtrack has artistic merit of its own, and that the fact that it wears its inspiration on its sleeve doesn't make ir any better or worse (objectively speaking), and still have certain individuality. This happens all the time when there is a cultural or artistic exchange. Another reason would be my comparison with tequila (¡VIVA MÉXICO!), which can ONLY BE tequila IF it's made in Tequila, Jalisco, or, to be more cosmopolitan, champagne, which can only be champagne if it has the proper point of origin.