I think you’re kind of missing the point with Washington. It’s not that he thinks he’s truly one of the worst Presidents, it’s that his allowance of the Great Evil called Hamilton to do as he pleased laid the groundwork for the truly bad Presidents to begin expanding executive power. You can even hear in a recent podcast Brion did with Tom Woods where he says Washington was one of the best Presidents we ever had, however it’s still important nonetheless to recognize what happened during his administration that lead to what we have today. He does the same thing with Madison in his annexing territory in a way that opened the door for Polk to start the Mexican American war. I’ve found that learning about history is often like seeing dominoes after they’ve already fallen; it’s about tracing what domino lead to the falling of each one.
Also he’s not going in order of which President is worst, he’s going in order of when they served because again it’s about tracing how each one lead to the problems of the next one.