Did not downvote them myself, but because of the seemingly kneejerk cynicism, I would imagine. OP is simply praising Go and sharing a success story - there's no need to jump in and point out (with a somewhat condescending tone) that other languages offer similar benefits as Go. While (maybe) true, it doesn't exactly take away from Go's accomplishments or how it's helped OP.
It's kind of like if I excitedly told my friend I'd run an eight minute mile, and she replied, "oh, so what? Lots of people can do that". Technically true, but unnecessary.
I believe that these days you need some secret threshold of karma (HN internet points) to be able to downvote. Now that you mention it, I have indeed seen way fewer power displays of the infamous "downvote mafia" recently, so I guess it works.
