When you hire people to write content, you don't have to attribute - you have paid them for the copyright, and once money changes hands you own the content and the copyright.

Stellabelle should have known this, because she has said she spent years writing for clients too...

No "scam" involved - just someone treating steemit like a business and instead of having a one-man operation, they have a team. It's not really that different from the curating teams the whales have hired, who also curate for money paid to them by the whales.