Do you know what you call a muslim that says sharia law is a backwards system with no place in the modern world? A liar. You can not be a muslim and not support sharia any more than a Christian can pick 6 of the 10 commandments .
Do not read into it, no Christian claims the power to change the commandments or pick and choice between them. Many Imams do claim the power to decide what the Koran says and allows.
