Considering this is based off Forbes list, and Forbes has Peter Thiel's net worth at ~1\5th the amount that's confirmed to be in his backdoor IRA, I doubt the accuracy.
Another easy example is that they completely miss the mind-boggingly wealthy like Queen Elizabeth II who was at the time the largest land owner on the planet and her wealth would lap everyone on that list. She was also a woman so they wouldn't get to complain about sexism in wealth distributions nearly as much.