As a female, I don't think there is an issue with the concept of having a separate Discord group for females only, even with the wording of it being a "safe space, free of harassment". I don't think this automatically means that they think males are bad or problematic and females are all good.
However, sometimes it is a welcome break to know you'll be in a group where you (most likely) don't have to worry about being hit on, sexualized, or garnished with unwanted attention...in whatever form that may take for you. Or maybe you just want to have a spot where you feel more able to discuss certain topics that men in general, for better or worse, do not handle well. It's not a crazy concept, and that doesn't make it sexist as some other people have been declaring.
As far as my own experience goes, I can't tell you how many times I've jumped on VC with a new group, only to start getting hit on by some of the guys. I've also had plenty that just creep over my in-game character as well. A couple of times in the past it's been so overwhelming to me that I ended up changing to a male character for awhile, and that at least stopped the in-game comments almost immediately. With that said, I've thankfully met far, faaaaar more people that are just fun and decent, but the other interactions can really stick with you and I really can't fault anyone for wanting to find a group of like-minded people who may help to curb all of that....stuff.
Now with that said, do I think it's possible to make a group that is completely perfect and free of trouble? No, not at all, but it's obviously worth trying for some people. And hopefully they have rules and people in charge who try their best to manage issues as they arise.
