females pat down females and men pat down men. That’s the way it has always been no matter where I have flown be it America or Saudi Arabia. The issue of modesty doesn’t arise in those situations.
And modesty might not be a “tangible” argument for you but to Muslim women, it is a very important thing. It’s not something that you can poke holes into or require something definitive.
Also, apart from modesty and religious aspect there is the issue of human civil liberties which is shoved down our throats as being such a “fundamental” right. A person has absolutely every right to avoid any kind of invasive procedure which ultimately makes them feel that they got a worst deal than anyone else. and, IMO, these women definitely did the right thing denying the procedure.
I don’t think any one of us can judge about body scanners until we’ve actually had our own scan done. It’s pointless trying to argue about it.