I understand what you are saying...but the math is all on Andrew's side. DERB might "look" like a bad player, but he consistently wins. Over a long period of time for a high rate. That's my definition of a winning player. It's not just the high winrate or the long period of time, it's the combination that makes the arguement/math compelling.
It can't explain it, but it doesn't make it less true. And anecdotal evidence is notoriously weak. See
Anecdotal evidence
It's a little like a trial, where the one eye witnesses say a person is the guilty, but the DNA evidence says it was someone else. The DNA evidence is so compelling and eye witness are somewhat unreliable, so we have to believe the DNA.