How about this. “In the interest of all of our customers. All pets, including service animals are required to travel in cages in the hold of the aircraft.”
There are disabled people, blind folks as an example, who trust their very lives to their service animals. A service animal is not a pet. A comfort animal is a pet.
The definitions of service animal and comfort animal have become blurred, mostly by the comfort animal people pushing the envelope that should never have been pushed.
It takes many months of rigorous training to prepare a service animal to do it’s job. Not so with a comfort animal.