Naming them by different names makes it sound as if they were diferent mediums. Manga and Anime are literally just the japanese words for comics and cartoons. I guess you could argue it references the specific cultural style, but then you got stuff like
''Batman and Son'' that is being called a Cartoon even though it was made by a japanese studio and it looks like seinen anime.

The diferences between the two are becoming less and less blury and it's starting to look even more like just a way for closeted geeks to not admit that they like watching cartoons.