Tell me, if a religion demands human sacrifices, will it be a private domain? Or if a religion allows you to sell your wife, will it still be private matter? Private matter remains private till the parties involved are in consent. When they are not, it is not private anymore. If a husband and a wife agree to divorce and live separately, rest is formality. Problem happens when they do not agree on something. Then it becomes the question of who is right and who is wrong. Whose rights are being infringed. And courts are best suited to decide that.
Brother, your are right. If any person tries to suicide, then that person will be stopped.
Selling wife is another thing and does not come under the personal law.
But the matter of 3 Talaqs is different. Muslim man marries with this condition that according to the Islamic Sharia, he has the right to say 3 Talaqs in one sitting. So, either the women deny this pact in the beginning. If not, and she agrees with it, and marry that Muslim boy, then Supreme Court now cannot annul this pact unilaterally.
Even in the Western democracies, if people make a marriage contract, then all the conditions of that marriage contract have the preference over the land's law.
Please brother, consider these questions and don't neglect them:
(1) A Muslim husband has given 3 Talaqs.
Now supreme court orders him to take the wife back.
But according to the belief of that Muslim husband, he will only be doing the fornication and becoming sinner even if the supreme court compels him to take her back.
No court can compel a person to change his belief. Simply the supreme court will fail here.
(2) And Muslim Women want supreme court to do it while they want to lead a "happy life" with the boy.
But this "Happy life" is not possible.
For boy, he will only do the fornication, which is a sin.
This makes the lives of both of them much more HELL than before. And the aim of that "happy life" which Muslim women or the supreme court is trying to achieve, is not going to be achieved.
That is why, the better decision would have been:
(1) Supreme court would have told the Muslim Girls, that according to the Sharia law, they could already stipulate the condition of nullifying the 3 Talaqs condition at the time of the Nikah.
This is the simplest solution, which Islamic Sharia itself presents.
But 99% Muslim don't know it and don't practice it.
Supreme court should have made it mandatory that Muslim girls should have been taught this Islamic right of their at the time of Nikah, and these conditions should be written on the Nikahnama (marriage papers).
By doing so, whole problem would have been solved and no Politics would have been involved.
(2) Other solution was this that Muslim women should change their religion and at least marry only those Muslim boys who don't believe in the practice of 3 talaqs.
(3) In the present scenario, the decision of supreme court is going to make lives Hell of many couples, while boy thinks he is being compelled for the fornication.