This is very misleading. There is no official Go slack channel. The slack channel you are referring is just a slack channel and is by no means official.
> In particular, Go developers, more than other cultures, seem to get an ego boost out of telling people "no".
This is misleading as well. Go was designed from the start to exclude certain features e.g. inheritance and many others. There are usually very good reasons for those decisions that people who've been following Go from its creation know and understand very well.
Now what happens when someone who does not understand those design choices comes to Go? They want their favorite feature obviously! When Go members attempt to explain them why something like that does not exist in Go (and probably will never be included) it starts feeling like "no". And people do not take "no" well. They get emotional and fail to see reason. If they had bothered to explore the language or at least read the official documentation and FAQ, that state of mind might have been avoided.
Including everyone's favorite feature does not make a language better.
Go has created a community around a certain school of programming. Nobody claims that it is better than other schools but it is a fact that it exists. But who is the one that is close-minded in this case? The new person that doesn't bother with the teachings of the school or the school that dismisses the ideas of the new person? Who is really the one that says "no"?
From my experience, the Go developers always carefully consider every new idea that is brought to the table. But it is also a fact that after the 10th time you've seen the same idea, you are not going to sit down and spend time considering it. You are just gonna link a previous discussion and say "Sorry this has been brought up before, please check these". How does that feel to a new person? I bet it feels like "no" again.