The paper itself is a lot clearer about the purpose. The blog post reads very clickbaity and doesn't really explain the context well.

I disagree, it clearly explains that AI carb counting apps are a problem and shouldn’t be used.

They’re writing in a neutral way that reaches their audience without lecturing or being condescending. They lead the reader to the conclusion rather than shoving it at them. I think that’s why it’s triggering so many angry comments on HN, but it’s effective for the audience they’re writing for (non technical people who may need convincing but don’t like being preached at)