So, I don't know this story, and I fully agree it's a weird reaction. But let me throw a possible reason out here..
When I was younger, a small girl in my neighborhood decided she had a little crush on me. Like, I was 16/17, she was like...6. I'd be walking in the neighborhood with my sister, she'd come say "hi" to us, then look straight at my sister and say "back off barbie". Was hilarious. And annoying.
Now, if I had somehow encouraged the behavior, it could have really made an kmpact on the little girls outlooks. Maybe the gf had witnessed something similar? Or been that little girl?
I know, I have no reason to think any of this applies. Just throwing it all out there.
(Weird, coincidental follow-up.. the little girl is now related to me. Her mom was my wife's cousin! Her life.. did not go great..)