Why doesn't Canada have the same battles over affirmative action?

Simple: the Charter says that its Equal Protection provision "does not preclude any law, program or activity that has as its object the amelioration of conditions of disadvantaged individuals or groups including those that are disadvantaged because of race, national or ethnic origin, colour, religion, sex, age or mental or physical disability."

It's litigated around the margins, but the basic premise of AA is firmly entrenched.

@jbe In the United States race is a zero sum game. A place where the poorest white person will forego very needed aide if a needy black person will also receive it. A place where the poorest white person will (paraphrasing President Johnson) will empty
his/her pockets to be able to call a black person the “N” word or a Gay person a “faggot” without any repercussions. Many citizens in the United States are diabolical and insane.