Why aren't certain champions considered "semi-ranged"?

I'm talking about champion considered as ranged but that have a really low range.

Rakan for example is the ranged champion with the lowest attack range even Graves or Urgot have more range than him.

Many melee champions champions are close to or exceed Rakan's range.

Why isn't there a range between "ranged" and "melee"? Or champions considered both melee and ranged?

Rakan even have a melee animation.