My definition of a safe space - in the context of the hive blockchain - is simply a community where you do not have to worry about the moderators muting you due to miscommunications or errors. Also, we have the freedom to approach the style of content creation in the way that we choose. Without being told to extend ourselves to match outdated criteria that is not very holistic. There are lots of ways to get to know a person apart from formal intros.
These two things are very achievable here, and certainly do not require a closed group. I realize that we all have different opinions, interests, outlooks and emotional states. Having a safe space isn't putting anyone into bubble wrap - we still have to be accountable for our own stuff. For me, it just means putting your best effort out there - and knowing that it means something. You are not just another cog in the wheel.