In his interview with NPR, what reason does Dr. Tyson give for leaving Pluto out of his solar system exhibit

Wasn't because he considered the planet a dwarf planet because of it's size, so it wasn't necessary to the general solar system? If he included all the dwarf planets and spacial bodies, our solar system would be even more ginormous.

Because he considered Pluto to be an icy body rather than a planet.