As explained on Wikipedia, the yari is a type of spear that was primarily used in Japan, and the yari pics I've seen aren't exactly tagged as such.
Posted under General
We don't always follow definitions from elsewhere, particularly if there are visual differences between what is one image population and another.
Whether or not people wish to lump simple spears with more complex types is a issue that needs to be discussed. If no one has any issues, then an implication can be made.
In Japanese the word "yari" is more general than the English word "spear". It includes spears but also all kinds of other pole weapons. If you restrict it just to typical Japanese yaris, they're more like swordstaffs than spears; they can slash rather than just thrust. They're basically like straight naginatas (post #1809229 has a comparison).
Though I notice that currently the spear tag is used for some things that I wouldn't consider spears, like Sailor Saturn's Silence Glaive.