You're misinformed.
Russ Cox took the time to explain why LLVM wasn't chosen: https://news.ycombinator.com/item?id=8817990
Russ Cox took the time to explain why LLVM wasn't chosen: https://news.ycombinator.com/item?id=8817990
And while Go compiler may not be perfect, it works well enough.
And while Golang may not be the fastest language out there, it is fast enough for most use cases. I mean, Python is fast enough for most use cases, and Python is one or two orders of magnitude slower than Golang.
So yeah, I think their compiler decisions are fine. They may or may not be the best decisions, however the article is not talking about the compiler part of Golang, so yeah it can still talk about "undervalued technology".