I'll leave the rest of your criticisms alone because I try not to argue taste or preference, only production and fact, but...
Why would the existence of any all-female org ever need to be explained? Trek has had scores of all-male leaders (the Fed president's cabinet in VI, for example, or Gowron's council) and villains (the Hirogen, essentially all of Dukat's various henchmen, the Xindi, etc) and never had the urge to ask why they're all men. Heck, IRL the US Senate didn't start to get decent female representation until less than 30 years ago -- but no one asked why the Senate was all men or would revert to being all men.
Their being female seems like the least of the criticism. Plus, we're still getting only bits and pieces of them. It's not like this show (or any show, Trek or not) is going to explain all mythology in one corner of its universe in a single episode. It took 5 whole series since the 60s to flesh out the Klingons, and there's likely even more to learn about them in future episodes -- and they have wayyy more screen time than the Romulans.