Every single definition that segments a real world set of continuous objects into discrete buckets has surprising edge cases. This is basically inescapable.

To steal a quote: All definitions are wrong. Some are useful.

I find that to be the most weird one too. I don't know much about orbital mechanics but in the unlikely chance 2 bodies shared an orbit does that mean they aren't planets then? How close can two planets be before losing that designation? I share your ire.

> If planets are required to clear their orbits, what was Jupiter called while the solar system was forming?

Hell, what's it called now? Jupiter's orbit is shared with millions of Trojans. Many of them are more than a hundred kilometers in diameter; for reference, Deimos, one of Mars' moons, has a mean radius of about 6 km.