That said, chometz cat food is a bigger issue than dog food.
Humans don’t eat dog food. BUT, every few years you’ll see an article in the general newspapers about impoverished elderly people who buy canned cat food because they can’t afford human tuna, etc.
Are those two statements intended to be related? Surely, someone who eats cat food due to poverty will be unable to observe many mitzvos. Chometz-on-Pesach would not be at the top of the list of their transgressions.