That argument is meaningless. The Courts do not examine religious texts to judge which precepts of faith are valid or invalid. 

Can you imagine Supreme Court justices pouring over the Christian bible and texts to determine what Jesus said or meant? (As if anyone belonging to the countless variations of the Christian faith can agree on anything that reflects 'God's wishes'!). So too are there myriad variations and interpretation of the Koran and Islamic faith (or Judaism, or Buddhism, or any other religion or belief system). Despite the tenets of organized religion and texts, the interpretation of one's faith are invariably a personal decision).

The test that the Courts apply is whether the individual is 'sincere in their beliefs'. Any woman with the courage and conviction to wear a burka in Quebec will easily pass that test. That (among a host of other reasons) is why this unconstitutional Quebec law will fail at the first legal challenge.