Ubuntu Marte - Is Discourse Really Open Source?

A truly open platform seems to me to be more appropriate for something like Ubuntu Marte, which is a desktop Linux distribution. There are far more ideological people in the desktop Linux space than there are in the kind of wider Linux space. It seems like the further away from the purists you get, the more acceptable it is to just be on Discord. And I would argue that I don't think it really matters what tool you choose for anything so long as it's the right tool that is most effective for what you want to do.