The safe and inclusive environment for one group is created by excluding another group
Don't know how you can say it ain't when it clearly is.
It's not exclusion to provide a safe environment for those who are
routinely and systematically oppressed in open spaces, period.
Picture a situation where, while walking the street, at least half of every person is openly carrying a semi-automatic rifle, and you're not. People with rifles will sometimes pass you by doing nothing, but some will point their rifles at you playfully or even shoot their rifles upwards near you for fun, some will even be enraged if you don't smile while they do so, not to mention all the cases where people with rifles injured or killed people without rifles just because.
This is the kind of threat of violence that women and LGBT-folks are subject to daily. In this example, anyone without a rifle would feel much safer inside a rifle-free environment, because they would not be subject to a constant threat of violence. As for the people with rifles, they already control every other environment, they are never at a threat of violence or exclusion, and the rifle-free environment doesn't change that. In our society, we have a duty to provide safe spaces for those who are excluded by those who control most open environments in order for these people to feel more comfortable and, eventually, more included.