Comment by wolrah

The question would be what are the specific rules that lead to that, and how you'd apply those rules outside of our own solar system. Any rule that just calls those distant objects KBOs is specific to our own solar system which is a silly rule to be making in a world where we already knew about hundreds of exoplanets.

The question at hand is "how do we define a planet" from a universal standpoint, because it hadn't really been defined beyond an "I know it when I see it" level and that was becoming a problem.

Objective rules that do not assume you're talking about our solar system are key here, and the serious proposals basically come down to 8 planets or dozens and growing, and from a practical standpoint the former was the obvious choice IMO since all it really affects is what gets focused on in general education environments.

If you just want to make an arbitrary decision that these things are planets because you want them to be as opposed to because they meet certain criteria, that's not useful to anyone.