But they didn't attribute it. Or does this not really matter?

Exactly the article brushes over this too, painting it as not abbig deal. But IMO it is a huge deal. Open source licensees have very few terms usually, making the terms that do exist extremely important to satisfy so that a user is in good standing.

This phrase in the article in particular is frustrating:

DeepDelver calls this “stealing intellectual property,” which is a bit of a stretch, since open source tools are freely available to be used, if they are properly credited.

Oh because my license terms are more liberal, it doesn't matter as much when you break them?? Really? Bonkers that they would publish that.

It does matter, that's one of the requirements.