You know what not racist/sexist?
Hiring people for their skills instead of their skin colour and gender
As it already is the case. Except in companies who take into consideration 'inclusion and diversity' quotas.
Regarding women, in gaming there are less women because most of their work positions are tech related and since they are babies on average women have way less preference by tech stuff than men, so when adult on average way less women decide to have a tech related career, they prefer other type of careers which happens the opposite: there are way more women than men. Plus there are other industries that are somewhat 50/50.
The difference isn't only in the companies, it's also in the schools and universities. And as happens in universities, women aren't rejected: there's simply way less women applying for certain careers, like in the industries.
TBH, 5% of tech workers being black in the US is pretty good. The total black population is only 12%. So I wouldn't consider 5% make-up in the tech field underrepresented.
In USA is there a big difference in the amount of money that on average have the persons depending on ethnicity? What is the split in US population and US gaming industry in the other ethnicities?
To work in tech maybe you needed a long education in pretty expensive schools/universities in USA, plus also have to spend a lot of time learning and practicing at home. Things that maybe only people from families with a certain amount of money can afford.
Maybe the difference comes from there: maybe on average certain ethnicities, in addition to be a way smaller part of the population, on average there's a smaller portion of them who can afford the required time and money required to start in the industry.
Maybe the problem is to turn a basic need like education a business that many can't afford, keeping some people out of the loop.