Why not? The 2 articles were in the PD after all, why be so retentive about it?
Not disputing that there are public domain articles.
Why be retentive? I recently had a very interesting discussion with a "research" firm that specialises in open source intelligence. Their attitude, with examples, was that by studying public domain information it doesn't take long before you start to build up what
might be a classified picture. The more open source you can get on a subject the greater the likelihood that you can piece together the classified picture. OS Int is a growing field, commercial, industrial, military - lots of money to be made.................. if you are good at it.