The go community reminds me of the java community. Blind faith in the design decisions of the language. Any feature it doesn't have is passionately defended as a good decision because the clumsy old way is subjectively clearer, up until the day it gets added.
I found that attitude much more prevalent in the .Net community: for just about anything added since C# 2.0 (I didn't follow discussions about generics after the 1.0 release though I expect it also happened then), the idea was essentially dismissed as pointless ivory-tower wankery useless to developers in the Real World right until MS announced it for the next version, at which point it became an Obviously Great idea and a good way to trash-talk java.
That sort of behaviour is in no way unique to Go or Java, and I think it's unfair to judge a language or community by some posts from an online newsgroup - most people are too busy to post or lurk on lists like golang-nuts.
mapping and filtering are just functions and/or loops. You can write those in go. Making some generic thing to save you 3 lines of (really simple) code is not an incredibly useful use of the Go author's time.
