They don't have to adapt to the laws of the land. They can go to prison like everyone else that breaks them.
But if too high a percent of them break them and go to prison, then that casts doubt on the worthwhileness of them immigrating here in the first place. Immigration can and should be evaluated purely on the basis of its benefit to Canada. If, because of average crime rates or average unemployment rates among a certain group, the immigration of that group is a net drain to Canada, then there is nothing wrong with placing limits on the immigration of said group.
Ideally, each individual applicant for immigration would be thoroughly evaluated and an individual judgement can be rendered as to whether to take him/her or not. But if we are to be too cheap and lazy to do so, judging people by the "risk demographic" they belong to, just like insurance companies do, is also something that can be done without it being racist or discriminatory.