That all seemed pretty adult and tame. Maybe slightly stand-offish at worst. And I tended to agree with Andrew in that thread. A project like Zig is an absolutely massive undertaking. I can cut Andrew some slack. Not everyone is perfect all the time, and his behavior there was nowhere close to BS I have seen in other open source projects. Ahem, Linus.
Did you read until the end of the thread? I was thinking the same at first but only because it took awhile for the conversation to play out.
From my plain reading he didn't take time to understand the proposal before providing feedback. That's fine as far as being busy or miscommunication goes, it happens, but after it was pointed out he never apologized or offered more constructive feedback. Which again is fine, but I'd expect a technical leader to not isolate the maintainers of their most critical dependency. Clearly he gave them a terrible first impression.