Her bottom line is the true message:
"Don't sign up for free photoshoots, read what you sign and also don't believe most of the things you read on the internet."
My guess is that she read and understood just fine but has now changed her mind, or even forgotten what the release said after many years. Contracts in general suck, I can't imagine the s*it I might have signed up to as an unthinking 18 year old! But that's the way it works and there's no point complaining about it now.
She's lucky the photographer was a decent person and has taken the image down from the stock sites for her, after a few years she probably won't be encountering herself in advertising anymore.