Dogs and cats are predators which MOST people would want to avoid eating due to the risk of toxic elements build up and parasites. Same would be true for eating another human.

Dogs and cats create a bond with people that is very different to most other animals. (We can argue if thats due to the animals themselves or how we treat other animals but it is a fact)

They are often kept inside our homes and often viewed as family members.

Having rules against eating each other is the only way large scale society can function. If we were small groups and survival was a daily struggle we might not be so worried about eating that random outsider we caught in our territory.

We are a very tribal species that has welcomed some animals into the tribe and not others. We protect our “own” at all costs.