Being anti-"DEI" is a trendy hobby for most, a serious concern for others, but for "Marc Andreessen, Mark Zuckerberg, and James Damore" it's literally the default, because DEI is a patchwork of inconsistent restrictions of various and often dubious authority placed on people who hire. It's against them, of course they're against it. They're against workers and labor rights in general, just like most owners.
You might as well say that oil companies are against environmental policies because the world has changed and they can no longer do what they used to do, and maybe they just got lucky anyway... or instead assume that most people are against regulations that restrict them from doing things that they might want to do.
edit: I suspect this might be a covert explanation about why this particular technologist is less enamored by the future possibilities of their chosen career than they were when they started it, just (for some reason) projected onto celebrities who have already been massively successful.