Most people in crypto do not understand anything about economics. They understand ponzi/ greater fool theory and how to obfuscate to the public and regulators to pull the wool over someone's eyes.
Thomas Sowell is a widely cited and studied economist. Many people study his work (including myself!). What does his being black have to do with anything? There is no group of people ignoring him for being black.
In fact, the contemporary politics would suggest that, since he's black, he'd be democrat, but his economics are very libertarian, a group more associated with racists. So what are you on about?
People don't "listen" to him because he's incredibly biased towards free-market economics, not because his skin color.