There are risks of disease and parasites from eating mammalian predators that are not a risk with fish.

Predators are also a lot more expensive to raise as domestic animals. Pigs are omnivores, and chickens will eat some small animals. We feed them what is cheap. Animal feeds do sometimes contain waste meat or fish.

People do eat reptilian predators. I have eaten crocodile and monitor lizard, a number of others are eaten.