I am EXTREMELY allergic to cats. If I bought something made in a house with cats, I'd need to wash it right away. If I bought something I couldn't wash, I'd be sick for a while, even after I got it out of the house. Say I bought a dry clean only sweater and put it in my closet. I'd have to get rid of the sweater, and then deal with everything else in my closet. I'd be pretty upset if I bought something without knowing it was made in a house with cats. I'd have to send the item back, and the refund would be the least of my worries, since my cat allergies have led me to the ER.
Dogs are a different story - we have three! I'd hate to make anyone as sick as I can been by not letting them know this. Also, despite my best efforts, dog hair ends up on things. I think people would be less grossed out knowing the hair on one of my items was from a dog and not a fat, greasy, old guy.
Announcing your shop has cats or dogs in it isn't about pleasing animal lovers - it's about not making buyers ill!