It wasn’t NASA tho - it was the International Astronomical Union (IAU):
NASA’s New Horizons mission made a close pass of Pluto this week. For more than 70 years, Pluto was one of nine planets recognised in our Solar System.
But in 2006, it was relegated to the status of dwarf planet by the International Astronomical Union (IAU). So why was Pluto demoted?
I like pluto but pluto only got his status as dwarf planet so a certain astronomers get less angry nonetheless Pluto is an asteroid.
"do you think that Pluto gives a shit? Pluto's not gonna quit, cos Pluto knows what Pluto is. And he knows that Pluto's HOT SHIT" -Tom Cardy
Always "Pluto, Pluto, Pluto". Why does no one ever remember Ceres, Eris, Haumea, and Makemake? They're each as much of a "planet" as Pluto is.
Space nerds: IS PluTO a plAnET oR ASTeroID Me: yes. Now shush and enjoy your pretty space rock