Please explain to me how legislation that divides people according to their skin colour and ethnicity isn't racist.
Note that there is a subtle difference between "racial discrimination" and "racism". Usually the two go hand in hand, people are discriminated based on race for racist reasons. It is not necessarily the case though. For a simple example, ordering additional tests to check for certain kinds of heart disease based on the fact that the patient is South-East Asian. It's racial discrimination, but it's hardly racist! You're discriminating based on race in that case in order to better the health of your patient by checking for disease they're likely at high risk of having.
So plainly it is possible to divide people according to their skin colour and ethnicity and not be racist. Let's turn to affirmative action. Is it one of those policies that discriminates based on race, but is not racist? Let's set aside for a moment the question of whether this legislation was ACTUALLY required in Ontario, and look at the question in theory. Is it plausible, at least in theory, that there are situations where racism is so pervasive that you have to discriminate based on race and set quotas in order to resist it?
Plainly yes.
Was Ontario in such a situation at the time that policy was enacted? That's much more debatable, but I think probably so. Are we still in that situation? I don't think we are any longer, honestly. At least not in the major cosmopolitan areas like Toronto. Perhaps in smaller towns it is still the case. When I look around my workplaces, and the workplaces of major companies that I deal with, I see quite a healthy racial diversity now. I really did not see that 25 years ago.