Yes. They are. But there's nothing against them being all male-shaped. I'm quite certain there is an evolutionary reason for Orks to become feminine shaped. Even if that is easily a million to one shot or greater. And in a Galaxy of billions of worlds, there is a good chance that one has Orks with what we'd call a feminine shape. Yes, they are. Along with Privateers. Now imagine what female Ork Corsairs are like?