But should that information ever have been publicly available? Someone else here linked to another instagram account publishing the same data, but that sure sounds like she didn't put it out there.
It's like saying that someone publishing your bank account balance or nude photos is fine, because someone once stole that data and released it on the internet.
No, it's not. You assume it was stolen, while it wasn't implied in that comment. They simply stated that the data have been put publicly at some point or another.