Even the "boy scouts" are just the scouts now: https://www.scouting.org/
Even the "boy scouts" are just the scouts now: https://www.scouting.org/
There is very much a need for boys to have a space to be boys: where they can let their boisterousness out, where they can act a little crazy, or just act closer to their true selves etc. without having to worry about how they're perceived by the girls. As soon as puberty kicks in, all co-ed events are affected by sexual dynamics; it's been a standard in every human society to provide plenty of contexts for boys where that is removed from the mix as much as possible in order to get better / different behaviour from the young cadre.
As the father of several boys, I agree. For anyone interested more in this concept, I recommend "Boys Adrift" by Leonard Sax (a psychologist) and "Boys Should Be Boys" by Dr. Meg Meeker (a pediatrician). Both books are very enlightening about some of the problems our boys face in America.
Basically, different safe spaces exist for different demographics, but are only marked for certain groups.
I'll add that one of the best things about Boy Scouts was that we could do stuff that was dangerous, but not too dangerous. We didn't have any moms come along either, and I think that helped. Dads would stop us from doing something truly stupid (like permanent injury type stupid), but not something dumb that would bruise us and teach us a lesson. It also allowed us to do lots more fun stuff.
These days, tree forts are a no-no, apparently. Some guys from my old troop were building one at a mixed event recently. Some girls from another troop came over and said it wasn't safe, then got some karen from their troop to come yell at the boys. Oh, and and apparently it's no longer okay to climb above chest height these days, because it's "not safe". I'm way too young to be saying, "Back when I was young, we did $UNSAFE_THING all the time! We liked it, and never got hurt." Or at least, I thought I was.