As i read more about Islamic law in light of all the parliamentary debates and motions being passed, i developed this understanding (please correct me if i am wrong) :
Syariah is divine. It entails very clear premises : that it frowns upon any miscarriage of Justice in the most natural sense (fitrah – ie, no killing, no stealing which are universal), it regulates relationship both among mankind and between the Creators and mankind, and it is all about grace and mercy.
Above definitions of Syariah, are all in the simplest and most natural sense. Anything this is Unjust, Cruel, and Blasphemous, are not Shariah anymore. 
The division, debates and arguments are at Interpetation and level of understanding, by men, for men. This is known as “Fiqah”. Fiqah happens when men began to interpret the extend of morality, divinity, and normative ambits according to their own understanding, studies, research or discources. It is no longer DIVINE. Fiqah, like non-Islamic Academics, is the main reason why islamic legal concepts differ from one culture, race, geographical location, time period, language; to another.
Even in civil law, the jurisprudences dffer from one to another. Reversal of burden of proof through the legal concept of “presumption” for instance, is a heavily debated jurisprudential topic in evidence law, as it is in direct contradiction with the established doctrine of innocent until proven guilty. 
So when one is against Syariah, he is against Justice, Mercy, Grace, and Knowledge. I do not think anyone should be against these values at all.
What people are against are “Fiqah” on certian law that they find in contradiction to their normative, principles and culture. such opposition should be directed right to that particular school of fiqah, and not Syariah. 
IE, if one Ulama claims that girl at 9 years old should be allowed to marry her rapist, that is the “fiqah” aspect of marriage. If everyone involve in that incident, find it just, fair, and mercy naturally (fitrah), it then becomes syariah to them. If it is not, then it is not syariah to them. But if you are against that particular understanding or acceptance, please direct it to the fiqah discourse, and not Syariah.
No one should be up against justice and mercy. When you are against syariah, you are against justice and mercy. Thats my understanding.