Yes, it is weird, but I disagree with your interpretation.
You wrote: "If there are asteroids and debris in it's orbit around the sun, it no longer counts as a planet." That Wikipedia link I pointed to says: "As to the extent of orbit clearing required, Jean-Luc Margot emphasises "a planet can never completely clear its orbital zone, because gravitational and radiative forces continually perturb the orbits of asteroids and comets into planet-crossing orbits" and states that the IAU did not intend the impossible standard of impeccable orbit clearing.[2]
It further lists a few attempts to define things more rigorously.
You write: "it's only purpose is to exclude the newly discovered planets from that classification". The same page also points out "In 2015, a proposal was made to use the criterion in extending the definition to exoplanets". This is from the same Margot, whose proposed criteria can "categorise a body based only on its own mass, its semi-major axis, and its star's mass."
You wrote: "If there are asteroids and debris in it's orbit around the sun, it no longer counts as a planet." That Wikipedia link I pointed to says: "As to the extent of orbit clearing required, Jean-Luc Margot emphasises "a planet can never completely clear its orbital zone, because gravitational and radiative forces continually perturb the orbits of asteroids and comets into planet-crossing orbits" and states that the IAU did not intend the impossible standard of impeccable orbit clearing.[2]
It further lists a few attempts to define things more rigorously.
You write: "it's only purpose is to exclude the newly discovered planets from that classification". The same page also points out "In 2015, a proposal was made to use the criterion in extending the definition to exoplanets". This is from the same Margot, whose proposed criteria can "categorise a body based only on its own mass, its semi-major axis, and its star's mass."