The Gleam community has been the best, most welcoming community I've ever seen on the internet. And I've been a around for a while. I attribute this in part to their clear stance.
I was welcomed too, and strongly encouraged to contribute. It was really nice. Though the signals might appear abrasive to some, it doesn't represent an abrasive group of people at all.
Joining their Discord and getting greeted by the language creator himself within a few minutes was pretty cool. Most other languages, their creators/maintainers seem so unapproachable and distant. You can talk directly with the core team on there, ask questions, etc. Louis really has built a pretty fun community around Gleam.
The good thing is, you don't have to be tolerant with the intolerant. And that's exactly what they are advertising. It let the nice people flow in, as you experienced.