Just goes to show that it's extremely trivial to clean up the final product with a few passes for quality assurance.

Single handedly, even. This is something one person could do on their own.

And yet they didn't even bother to try.

If they really intend to sell such images, it's extremely unprofessional to leave the botched examples in the mix, despite efforts to rationalize why they should be included.

Based on that, I suspect it's one person acting alone, and it's a get rich quick effort to take the money and run.