for example, in Greek legends, cyclops lived separately and didn't serve any orcs.
sirens killed the entire ship, not 30% of the sailors...
medusas didn't shoot bows, and you couldn't even approach them, but here they don't even turn you to stone immediately... and so on.
a free cyclops hasn't forgotten how to hold a stone; it's just difficult with a club, the stone is heavy, and you need two hands. but a goblin is so small and convenient, it just jumps into your palm.