FUNNY STORY #4

Brianna was getting out of the car the other day and said, "Shitzoo". This is how the rest of our conversation went:
Me: "What did you just say?"
Brianna: "I said shitzoo."
Me: "You don't say that. That is not nice."
Brianna: "You can say SHITZOO if you are talking about a dog." That's what I'm talking about."
Me: "Well I don't SEE a dog, and we weren't TALKING about a dog, so you don't need to say it."
Brianna: "Well, it's not a bad word. I'm putting zoo at the end of it, so that means its not a bad word anymore."

What do I say to that?