I also read the older post of his that he linked to, and overall he just sounds like an asshole, or, perhaps more charitably, someone who does not understand how social situations work in the real world. How you treat other people when you communicate actually is important. It might even be the most important part of interacting with other people. We are emotional human beings, not robots. He calls all this "tone", which just sounds like a way to trivialize the entire thing and justify treating people poorly.
It does sound like the VTE maintainer has some ego problems and sometimes doesn't make good decisions about changes to VTE (even one of the GTK maintainers seems fed up with him). But that's not a blank check to act like an asshole toward him.
More importantly, I wish people would think about outcomes more. Do you want to rant on the internet about how right you are and how stupid everyone else is, or do you want your bug fixed? It's funny that the author talks so much about how the only thing that matters is the experience users have, but then directly contributes to creating a situation where the maintainers don't want to work on the issue at hand. Instead, he could have been polite and respectful, and maybe the fix would have gone in much sooner.