This doesn't explain that hatch will package everything in the project directory by default. As a new user making a package, why would you think to look for hatch configuration options?

I mentioned in the article (maybe you don't read that carefully?) that hatch can be configured to do what you need, but if you're just following the packaging guide, which doesn't mention this behavior or provide any kind of heads up to new users, you won't be aware that it is going to even try to look at a directory like .jj. And why would it? I wouldn't expect a compiler or a tool like Maven to look at files that aren't needed to build the project. Why does hatch?

Your demonstration just shows if you're already aware of the problem and you know the cause of the problem, you can find a solution. I say as much in the article and agree with the point. The point of my article is this is surprising default behavior and it's better to just use a tool that has sensible defaults.