I do not understand your friend taking offence. It is not a condemnation of people with pets, it is a statement of fact.
I warn everyone who enters my house that I have pets and keep their shoes on or their socks will get dirty.
Me, I do not worry about a bit of pet hair, but I do not like the smell of cigarette smoke. All used books I buy have to pass a sniff test and I will not lend a book that I may want back to a smoker. If I know I will not want the book back I do not worry about who gets it.