Because mine (3yo) doesn't.
Not that I worry. I wouldn't even notice, but it's obvious that other people think she must have names for her babies & animals.
"What's the name of your doll/giraffe/zebra?"
"Beebee", "jraffe", "'ebra", she replies, factually confirming the obvious.
So I'm curious ...If your DD names her dollies/soft toys, did you teach her to do that? Did she learn it from other children? From TV? Did she do it spontaneiously?