There are “safer” spaces, and there are places that can be safe to a specific group of people at a specific time, but there’s no such thing as a universal safe space, because the precautions that make a safe space for someone invariably make it unsafe for someone else.
A while ago, I was talking to a vegetarian who was (understandably) upset that she would be invited to parties where everything contained meat. Her proposed solution was that everyone should always cook vegetarian for parties, because that way “everyone” (vegetarians and omnivores) has something to eat.
The problem with that is that it’s a “catch-all” solution that doesn’t actually catch all problems. Even if you expect the mostly-carnivores who don’t like vegetables to “tough it out”, you’re still left with nut allergies, soy allergies, milk allergies, celiacs–hell, I know someone with a sensitivity to raw vegetables. There’s no way to accommodate everyone 100%. The best you can do is be aware of everyone’s issues (by asking and remembering) and label things appropriately.
“Safe spaces” online can be pretty much the same way. Making a space perfectly safe for people with body-image issues can make it hostile to rape survivors; making it safe for rape survivors can make it unsafe for recovering alcoholics. If you want to cater to everyone, the best you can do is provide awareness and “ingredient labelling”. Attempts to police for everything “unsafe” will pretty much leave the board at the mercy of the mod’s biases (like that vegetarian I mentioned above) where they might strictly stamp out all sexist, ablest and racist behaviors…but simply don’t see (for example) anti-religion attitudes.
The perfect is, as they say, the enemy of the good.