It means people make posts like this poster has made here. (This is an honest answer based on my experience.)

actually this very accurate, but it doesnt make anything i said less true or accurate

tons of bikeshedding posts, ones that criticize D lack of vision/focus and misfortune

We moderate with a light touch to allow our users as much freedom as we can. People can write negative and bikeshed posts, and they can criticize me as much as they like. But we do moderate posts that make personal criticisms of other members, go off topic too far, or engage in unprofessional behavior.

I heard Discord may have negative posts as well but I find the official D newsgroups (with a forum interface) very friendly and clean. Minimal moderation seems to help there.

I'm one of the moderators on D's Discord server.

We do our best to ensure everyone feels welcome to join in. Of course none of us have social media training and are just doing our best.

If something is going down and we are not taking action it may be because we are not aware of it being problematic and are always open to hearing complaints as they come up!

The Discord is quite nice, you should join =)

Actually bikeshedding is discussion about software architecture. And software architecture is an absolutely valid discussion theme outside of stackoverflow.

To be honest, this just described your grand post.