It's their business. This is America and this is religious liberty. If the women don't care to submit to Islam's laws they can go elsewhere.
I'd be upset if the DC police went and shot a woman to death because she switched to a better religion, but not when all this involves is the seating chart in the mosque.
What this is another example of how Muslims use our freedoms to advance their agenda.
When visting Europe, RC Churches had women and children in the front and the men in the back.