You could add a hydrostatic equilibrium requirement, which is what the IAU definition does. It doesn't really affect anything else the GP was saying.

Why did we add this requirement? To fit how you want to classify planets? That retcon was not executed well.

It shows that the line of reasoning makes no sense, because any classification is constructed to fit some of our preconceived notions. Choosing a classification that builds off our social history is perfectly fine, as long as the rules for classification are applied consistently.