Tell that to society at large. No man is an island.
It's a sensible default and should be enabled as such. They wouldn't know the difference if it already were. If they can articulate a specific and valid reason as to why they don't want it that way, then fair. It should be an option open to change. It simply being 'impolite' is somewhere between 'open to interpretation in specific cases' and 'wrong'. Many aspects of what is normally called politeness are constructs that have no or limited use in the current world. This is one of them. My conclusion is thus that their reason is invalid.
I'm making some assumptions. If any are counter to the reality of the situation, then there might be good reasons not to change it.
Edit to your edit:
> That's not very consistent. You wrote that whether they should was another question.
Emphasis is a common literary tool.
> This didn't happen here. No doors were closed without a good reason, because there is one.
I disagree on the reason given being good.