Some of us have worked for corporation where all problems were sugar coated in nicely sounding phrases. They got hidden so nobodies feelings are hurt and criticized person did not even recognized there is a problem with his work.
The whole system becomes dysfunctional in its own right.
And some of us have worked for businesses where everyone is so busy being aggressive and showing how much of an alpha male they are that nothing gets done and all the customers are scared off. Not to mention potential employees.
Whether or not Linus admits it, the same thing is happening with the kernel (wrt to contributors, the "employees" of an open source project). I know system developers who could make valuable contributions to the kernel but who refuse to work in that kind of atmosphere. And I can hardly blame them.
So, if we can't work in sublime subtlety, we better become savage barbarians, as if “balance“ was hostile to civilisation. To not insult and to not swear is not to speak in “sugar-coated phrases“.
There is a difference between sugar coating and showing a basic level of respect. Clearly expressing valid criticism without resorting to vitriolic language is something most people will have to work on, but as you say, it's very important for a functioning workplace.
The whole system becomes dysfunctional in its own right.