https://en.wikipedia.org/wiki/A_City_Is_Not_a_Tree
Your brain doesn't organize information hierarchically. Let's say I ask you:
1. Name a band that starts with "B".
2. Name a band from England.
3. Name a rock band.
If your brain stored bands in a hierarchy, you'd only be able to come up with "The Beatles" as an answer for one of those questions. You'd have to figure out whether to categorize the Beatles by name, location, or genre and it would be absent from the other categories.