The same people who were working on generics in Go prior to v1 were also still there to help out when it eventually landed, so whatever stones, clubs, and pitchforks you saw weren't compelling enough to scare one away from making it happen. Not that anyone would expect them to. Meaningless distractions don't get in the way when doing something is worthwhile.

But obviously "go doesn't have generics lol" comments on HN were even more important. Just think of what would have happened if that wasn't repeated multiple times daily for years and that effort was put into getting Go generics into place much sooner. Count your lucky stars or something.