Sometimes. Sometimes not. Depends on the individual dog.
Some dogs will kill anything smaller than them, but be submissive to anything bigger than them. Unfortunately, in my experience, these dogs are often fear biters. They’re also prone to attacking children their size or smaller. I would trust one roughly as far as I could drop-kick the Taj Mahal.
Some dogs are aggressive to most animals, regardless of size and species. They’ll attack cats, other dogs, adult humans, whatever. On the whole, I’d rather deal with these dogs, because at least you know for sure where you stand with them and you never have to worry about someone mistaking them for a non-biter.
Other dogs are hell on non-human animals, but don’t have a speck of people-aggressiveness in them. Unsocialized pit bulls tend to be that way. Very dog aggressive, very strong prey drive (with proper socialization and training, this can be refocused), but almost never aggressive toward humans unless they’ve been attack-trained.
Unfortunately, it can be really, really hard to tell type 3 and type 1 apart. It’s not uncommon for people to think they’ve got a dog that’s only aggressive to other animals, then realize they’ve got one that’s aggressive to anything smaller than it. All too often, they realize this after someone (usually a child) has been bitten rather badly.
Of course, any dog that will kill a cat or other small animal will bite the everloving fck* out of somebody trying to stop the carnage. I’ve seen people get a couple steps from an outright mauling trying to beat a dog off another animal.
Long story short: Some critter-killing dogs are fine around humans, but you couldn’t pay me to have one around my family. YMMV.