Michael Meyers is clearly a person, though you might describe him as a "monster of a person". I'm taking about killer sharks and whatnot as "monsters".
I think the sandpeople are clearly meant to be people. They wear clothes, they fire guns, they eat McRibs = People. Perhaps uncivilized, or monsters of people... but people.
Whereas a Wampa is meant to be a scary monster. Grrr!