They call it a “scam” but there was nothing dishonest about it. He gave them what they wanted and they gave him what he wanted. Sounds like a straight up transaction to me.
Of course they are utter fools. The cat is out of the bag as far as 3D printing of guns. You are never going to be able to stop the 3D printing of guns. Efforts to constrain/reduce supply were always doomed to failure and were always a fool’s errand.
You are correct. A willing buyer and a willing seller come to an agreement for a transaction isn’t a scam. It’s a business transaction.
I compare 3D printing to The Weapons Shops of Isher by A. E. Van Vogt brought to real life. If you haven’t read that 1940s era 2A Science fiction, it’s worth the quick read.
https://smile.amazon.com/Weapon-Shops-Isher-van-Vogt-ebook/dp/B00GSZU26S