Hippos can run at like 30km/h. If the 100 people pissed it off it's going to ram through them like a small truck and then just turn and do it again. And hippos will actually engage a larger group simply out of fucking spite.
Also for the record, an adult male Hippo can get up near 10,000 pounds. So it still has like half the combined mass in a single package that can move faster than any of the humans and will kill them by accidental contact.
Seriously, these things can pick fights with river boats and win. Straight up smash the boat to splinters and kill everyone on board.