Saturn’s Sixtieth

How come 1.2 miles wide merits moon status while Pluto doesn’t rate as a planet?

Saturn’s sixtieth moon discovered

“A new moon has been discovered orbiting Saturn – bringing the planet’s latest moon tally up to 60. The body was spotted in a series of images taken by cameras onboard the Cassini spacecraft. Initial calculations suggest the moon is about 2km-wide (1.2 miles) and its orbit sits between those of two other Saturnian moons, Methone and Pallene. The Cassini Imaging Team, who found the object, said Saturn’s moon count could rise further still.”