Well, I'd have to agree with them. My peers are generally happy using Slack, Discord, and other proprietary solutions.

Though I'm not convinced that greybeards are any different, just the ones you find caring about it on the internet.

My dad's a 68-year-old old school embedded hardware developer and he'll use whatever toolkit works. I reckon most people in the world are like him and not obsessing over tools, despite what HN makes you think.