"Safe spaces" are this invention by modern regressive leftist social justice warriors that might have some good intentions behind it, but are in fact more detrimental than useful in practice, even to those who they are intended for. Not to talk about them being outright illegal in many cases, because they engage in gender and racial segregation.
Even if we ignore the legality question, they are still detrimental to everybody involved, even those who they supposedly benefit.
Social justice warriors will argue that "safe spaces" are courtesy to those who have suffered some trauma and may be "triggered" by some event, and thus can avoid getting depression or panic attacks.
In reality, at least 99% of people who take advantage of these "safe spaces" have never experienced any kind of traumatic event, abuse, or even hardship, in their lives. They are mostly spoiled rich university student kids who have been brainwashed by this regressive leftist victim cult into thinking that they are oppressed and marginalized by society.
And that's one of the major problems with these "safe spaces": They are echo chambers that serve only to reinforce this brainwashing. They are like cult meetings, where the cult members are being spoonfed a victimhood mentality, isolated from the rest of the world, isolated from criticism and differing points of view. Isolation is exactly the tool that cults use to keep their members brainwashed. They are told that the outside world is a big scary place, where they will experience persecution and discrimination, and that the only safe place for them is inside the cult, safely separated and isolated from the rest of the world.
When a "safe space" is race-based, then it only helps reinforce racist attitudes, rather than alleviating them. Not only is the racist mentality of the people within the "safe space" reinforced, it also creates resentment and animosity in outsiders who experience the real discrimination for being barred entry solely because of their race, even when they would have a good reason to enter. Racial discrimination only reinforces and enhances racism, not the opposite.
In other words, safe spaces are (intentionally or not) a mechanism to reinforce a false persecution complex in their members, by isolating them from other views and criticism. It's much easier to paint the outside world, other people, as monsters when you don't have any contact with them.
This is also one of the reasons why these "safe spaces" are also detrimental even for those who have experienced some traumatic events, such as rape (real, brutal rape, not the made-up "rape" that most of these social justice warriors claim to have experienced, which often amounts to someone just flirting with them, or inappropriate words.)
Rather than get better and engaging in a psychological healing process, these "safe spaces" only, and again, just reinforce their fears and their victim mentality. In this particular case the victim mentality is based on an actual event and is justified. The problem is that these "safe spaces" are not helping it; they are only reinforcing it. After a traumatic event you don't get better by isolating yourself from the outside world, by living in a societal bubble, without ever having to confront your fears. That's the worst possible thing to do. No psychologist or other similar professional has ever recommended isolation as a cure for psychological trauma, but the exact opposite.