Because the stat-block was originally copy-pasta, that's why.
This great beast looks like a bear with the proportions of a tiger. It runs towards you, a hungry gleam in its eyes.
Agriotherium is not a true bear, but rather a hemicyonid, close relatives of bears built for running. Rather than the omnivory of most bears, Agriotherium is a true carnivore, feeding mostly on the flesh of elephants, rhinos and other huge beasts, although it can and will scavenge and feed on fruits, grubs and honey. Agriotherium hunts in pairs or in small packs, and these groupings are very territorial--they are likely to view intrusions of humanoids into their ranges as a threat.