He's comparing the zealotry they're displaying which is similar to Protestantism. It's not saying they are Protestants. I think you missed the metaphor. There's most certainly a cult-like religious element that's being displayed in silicon valley right now. That innate human behavior isn't relegated to old Abrahamic religions. People will get drawn into "worshiping" different things and there's a very specific "God" being worshipped by these companies.