Many people love and feel responsible for their elderly and incapacitated parents. Should companies allow workers to bring their parents (possibly with dementia) to work with them?
I am saying it's not signaling wealth or virtue to take care of your pet. Some people really love their animals, and are willing to part with their money for them. Using your example, I would never begrudge someone spending lots of money on their family either.
It seems you don't like pets, and that's OK. It's also OK for other people to love their pets even if it doesn't make sense. It doesn't have to be signaling.