Actually, I would argue that his opinion that tech is not racist is in the mainstream. It would not cause an eyebrow to be raised in the vast majority of tech offices I've worked in. That's the funny thing about a lot of these arguments against "political correctness"; the opinions most folks who use that term hold are the ones that white men have held for centuries. It's not at all surprising that there are still lots of white men that hold those opinions. And, given the incredible imbalance of white men in tech (even taking into account the Asian factor, the US tech industry is still a strikingly white and male industry), it is not difficult to hold those old positions without ever being questioned or challenged on them.

It's only because these views so rarely get challenged that it causes such a fierce response.

Source: I was one of those white guys who thought tech was a super great place where anyone with the skills could get ahead and there was no glass ceiling for women and their was no reason black folks couldn't do great in the industry if they just had an interest in tech. I recognize all this because I was there. I just wish I had a better way to help other people understand how their privileged position makes it very difficult for them to see and understand why the tech industry has both an extremely sexist and white supremacist culture.