"And, sure, the guys behind it had made some of the biggest contributions to computer science to date, including: UNIX, regular expressions, Plan 9 and even UTF-8!"
It's a little far-fetched to say that two operating systems and a string container are some of the biggest contributions to computer science to date.
But it isn't that far-fetched to say that some of the people behind Go did made substantial contributions to computer science. Which is indeed what he wrote. Whether those four particular aspects of their work are the same ones you'd point out or not.
More to the point though, it is a dumb reason to use a language. Though not a dumb reason to pay attention to it or its design.
If we're talking computer science then I kind of have to agree that Unix and regular expressions are minor contributions if they even rank at all. There are several theoretical concepts and core algorithms which are much much more significant.
On the other hand if we're talking about computing and programming in general then they are pretty damn major, possibly on the top 10. One has to remember that CS isn't programming and programming isn't CS.
It's a little far-fetched to say that two operating systems and a string container are some of the biggest contributions to computer science to date.