No offense, but I've met some really poor excuses for human beings, and in a lot of cases, I'd happily choose a wonderful animal over a pathetic human.
Animals never mean you any harm, and as long as you treat them with respect, they'll never, ever hurt you. People, on the other hand, can be pretty fucked up sometimes. So, if it's a choice between a loving pet and a disgusting human, I'm not going to automatically save the human without thinking it over first. I think you can tell more about a person's true nature by observing how they treat all animals, not just humans (who are, of course, also animals).
For the record, I've stopped for injured animals and humans alike...
...but that doesn't mean I'll always choose a human over an animal. Especially if the human is one of the all-too-common trolls that have taken over this thread (and the rest of the site).