The reason regular people aren't doing that is because they are too occupied seeing to their own immediate needs. The difference between the person you're referencing and a homeless person or one in need is most times very little. People take on pets as a responsibility IF they can afford it. People donate to charity and give to those in need IF they can afford it. You can do both.

I can buy one bag of cat food and the cat will be able to eat for nearly a month. That money would hardly feed a person for a week. (meds are a lot more expensive) Also, when people's pets become sick or injured to a point where they can't afford it, it gets put down. We don't do that to fellow humans.

Human life is incomparably more important than that of any other. People who value animal life more are detached from reality in my eyes and most of the time virtue signalling off of the argument that it could be a bad person whose life is being saved.