Your point being? We had Wilfried Laurier in the 1900s as PM of Canada, it didn't changed our sub-cast status. What's relevant is how, on average, the cohort is treated by other members of the society when it comes to rights and privileges regarding work, law and education.
Are the sub-standard jobs in the U.S. are mostly done by a specific ethnicity? If so, then you have yourself a cast system. As unintentionnal as it might be.
End of Cikomyr's quote
I cannot comment on the canadian sub-class (or lack there of) as I said, my ancestors bailed on it long ago. However, I can comment on it here. There is racism, there is discrimination. Just as there is discrimination against Catholics, Jews, one legged polo players and red haired, green eyed color blind parachutists. But that does not make them a subclass. Unless they want to play the role. Laws can make them that way, if passed or not enforced, But discrimination is just that. Discrimination. not a definition of a class.
And your last statement is patently false. In the first place, who does a job is not proof of who is allowed to do it. You can use it to establish an hypothesis on perhaps some discrimination, but not as proof. Are men discriminated against when it comes to secretarial work? hardly.
And the second reason is that the occupiers of those jobs are less educated. In other words, they cant do anything else. And so who are the less educated? for the most part, illegal immigrants (they did not have access to education in their native lands). That we share a long border with Mexico means that most are from taht country (Mexico makes US laws about illegal border crossings look like a cake walk compared to what they do on their southern border). And of course, if you are a blond haried, blue eyed mexican, you are still classified "hispanic" (don't laugh. I know some). Again, making assumptions without investigating the underlying symptoms is very dangerous - and usually wrong.