Virtually every financial market is rigged these days. Paul Craig Roberts and others write about this quite often and how it wouldn't have been possible until recent years because Washington only became utterly corrupt in recent years (as opposed to mostly corrupt).
"Official" government statistics are almost always lies. "Reality TV" is scripted, the "news" is a combination of mindless fluff and propaganda. The American system is one big lie designed to benefit the banks which are "too big to fail," the large corporations which are "too big to fail," and sports-"entertainment" entities like the NFL and NBA that are "too important to fail" because they promote "multiracialism" and cultural communism.
So it would hardly be a surprise if the NFL, which classifies itself legally as "entertainment" rather than sport, isn't fixed to a degree. It would be more surprising if it isn't compromised to some extent, because virtually everything in this fallen society is tainted by the evil in charge whose agenda is to bring everyone down to the lowest common level of animalistic conduct and values.
My disagreement is with those that claim that games in which White players don't do well must be fixed, but they never make the same claim when White players do well and black players poorly. There's never been a pattern based on race established, only selective griping. If games are rigged it is for financial gain and/or to enhance interest in the league and its "entertainment."