Supporters of the IAU definition (which I should add was a deeply biased sample, in that it looked like they were headed toward no definition or a hydrostatic equilibrium definition, so most supporters of that left, but the people trying to switch it to an orbit-clearing definition stayed) will argue that it's cleared if the remaining objects are trivial transients or in orbital resonance. But that's not what the IAU definition says. Also they'll point to the Stern-Levison parameter, but (A) that was based on the ability to scatter today's distribution of asteroids, not the primordial distribution, which included outright planetissimals**; and (B) Mars didn't even clear it's own orbit, Jupiter did. Also, in the paper that introduced the Stern-Levison parameter, they argued for a better definition where you combine adjectives and nouns (each with specific implications about the body) as needed to describe its size, composition, etc.
But the OP's point stands, in that it's stupid to say that something is a "dwarf planet", yet not a planet. It's like saying dwarf stars aren't stars or dwarf galaxies aren't galaxies or whatnot. An adjective-noun is almost always a noun, that's how language works. In the cases where an adjective-noun isn't a noun - say, "shooting star" or "slow worm" or whatnot - we treat these as scientifically erroneous colloquialisms, and formalize corrected scientific terminology. We don't do literally the opposite and have science codify misleading language.