Me too. "Your email isn't your data". etc. That's EXACTLY what it is. She's already said she's got a unique name.
If you wouldn't be happy to sign your full name under each of your public posts then you shouldn't be dismissing this.
And regardless of whether you personally would be ok with it, the forum's systems should be set up COMPLETELY with data protection as its very foundation. The fact that this could even happen accidentally is incredibly concerning.
Doxxing is massively serious. Have people not heard of police being falsely called out, workplaces and family being targeted etc?