Thoughts
Reading HTWFAIP: It's paradoxical. He assumes that you're fighting uphill and you need to be nice to people for them to do things for you.
There are certain online communities, like open source software development, where the base assumption of the community is that you're working together to create something useful and valuable. In this setting, there's not a need for social lubrication (not need, maybe it's still valuable) because everyone is already acting selflessly. Not for the good of the other person or for themselves, but for the good of the project. Normally this environment would be very rare, something that was only achieved during long work sessions in the same room as trusted, long-term collaborators. In this environment, you can tell someone they're wrong bluntly, and it doesn't effect their ego because it's not an social interaction. They're not thinking about themselves or you, they're thinking about the problem. But for a certain type of person, this culture is intoxicating. It feel like running downhill. And so we use this style of communication online with strangers as well. In a way, I'm agreeing with Carnegie—it's not worth arguing. But to the untrained eye it can look less polite.
Here's a fun example
=> https://github.com/kristoff-it/zine/issues/167