Part of the reason Pluto’s classification hit so hard in the US is that it’s the only ‘planet’ ever discovered by an USian astronomer. That national pride made the 2006 decision sting more than elsewhere. Some of the top figures from the AAS even challenged the legitimacy of the decision afterwards.

(I copy-pasted this comment for the third time even though I don’t like to do that, but it’s important to know where does such reaction come from : partly from pure national pride)