She belongs to a canine species and she even used honorific, not nearly as rude as you're making it out to be. Still a bit rude as she could have simply asked for her name but it's similar to a child calling an older half elf girl "Half Elf-oneechan". Plus, to them they are just bodyguards not retainers.
What would have really been rude is if she was there for the entire meeting and still call her that knowing her name or knowing she's a member of wolf clan.