The reason you heard about diversity in Hollywood is because people in the industry are aware of the problem, are talking about it, and are working on it. The reason that people are doing all those things is because they're liberals.
In places where diversity is really a problem and nobody is working to fix it, like corporate management, agriculture, engineering, sales , and financial services, their diversity efforts are not really making news because there are few to no efforts to make the workplace more diverse. And guess what. Very few liberals.