It's easy for you and I to say, "these women could just leave or take legal action" but we both know it's not that simple. I think there are many parallels between what a Muslim woman would face if she stepped outside the Sharia process and an abused or battered woman trying to leave her abuser, when the rest of the world sees him as a "nice guy". If you grow up in a culture where as a woman you're treated as a second class citizen from birth, I don't think it's like flipping a switch and suddenly being able to adapt and take advantage of the freedoms and equality that being an American offers you. They still have to live in that community, they still have to raise their children and face their own family.
Please, come to the rural Bible belt. I have some women I would like you to meet. Ignore the broken nose, black eye, and weird limp. She just ran into a door and then stumbled down the stairs. She doesn't have a negative thing to say about her husband because her religious beliefs, and those of the community she lives in, are that she is to be subservient and respectful of him at all times. And ignore the rumors that she was forced to have sex with her husband at gunpoint. Just because the community thinks that marital rape is not a thing doesn't mean it actually happens.
Her son? He broke his arm on the playground.
I see this adoption of Sharia in Texas as nothing more than finding a publicly informal but privately brutal way of oppressing women and ensuring they are under the foot of their husbands and don't dare divorce or be treated as an outcaset in their own social circle.
But it is just not sharia law. I still have yet to see anything different between them and what I see some very conservative Christians doing. Every aspect of that lifestyle is despicable, but it is not just sharia law. People like Breitbart ignore that this kind of stuff happens to white, Christian women every day, but attach it to the word Muslim and it is a crisis.
If you really want to stop that behavior you won't act as if those who follow sharia need to be acted against, but that anyone, anywhere who acts that way should be acted against. Outlaw the behavior in all instances. Currently, many places have laws where if the battered spouse won't press charges then police cannot legally intervene. I saw it happen with a friend just a week ago.
I suspect that the issue is that people who react to this think that this behavior is so horrible that it is already dealt with and then you get a news story about sharia law and everyone thinks they are the only ones living this way because they openly state it. If someone is going to live and think in a deplorable way I would prefer they be open about it. At least then I know who these people are. It is far easier to identify those that need help than the stay-at-home mom (because women shouldn't work) who only goes out for groceries and church.
Depending on the place and local laws spouse abuse is illegal already. You can't make it more illegal or force a specific religious group to face new specific laws that would bring it to light. You can't force someone to recognize a divorce or think differently. The only way to help these women is to break through their upbringing or beliefs so that they will feel it is OK to seek legal action. The law is doing all it can without police being present at the time of the abuse.