The ecosystem ones are open to anyone who has an Atlassian account, but a lot of it is read-only. The content tends to be clear that it's about Atlassian and I think a most people who stumble into it will take one look and think "this is nothing to do with what I want to ask/write about/raise" and simply go back to something more recognisable.
As an example, I've got this lot:
I know what most of those Jira systems are for (heck, one of them is my own). I just followed the link to the one I don't recognise and the content immediately screamed "Nic is not a contributor here"
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