I want to see graphs of moves the author randomly made too. Maybe even plotting a random-move player on the performance graphs vs. the AIs.
It's beginner chess and beginners make moves at random all the time.
1750 elo is extremely far from beginner chess. The random mover bot on Lichess has like 700 rating.
And the article does show various graphs of the badly playing models which will hardly play worse than random but are clearly far below the good models.