It's not an original idea. It was popularized a few years ago by Evan Ratliff, author of a book about Paul Le Roux, 'The Mastermind'

Convenient for the author to discover the link to Le Roux. Then talk about it on podcasts while promoting his book, and have articles written about him.

All Shkreli does is promote himself to get eyes on whatever he's doing next. You can't ignore the incentives. It's difficult to prove who Satoshi is or is not. Craig Wright made a succesful career out of it.

Also, Shkreli has been critical of Bitcoin. Picking Le Roux, a criminal, as Satoshi helps to paint Bitcoin in a bad light.