Categories generally spring about naturally, but over time they become perverted by morons who cannot think outside the box.

Berries are an example. Everyone knows they refer to small fruits that you can find in the bushes. Blueberry, Strawberry, Raspberry, Chokecherry, cranberry, huckleberry and so on.

By attempting to create definitions of categories that are more stringent, categories begin to work against their own purpose of grouping similar things together. Happens with planets. We made a group of them because they were all just giant circles we could see in the sky. Until some autists decided one of the circles doesn't really count. Did it suddenly stop being a gigantic circle, or something?

The same thing transpires here. An arbitrary need to create strict definitions, even when they clearly don't correlate to reality. Laying down some rule that every ten years, a game becomes retro. Stardew Valley has just joined the ranks of the retro, because it turned nine years old. According to idiots, anyway.