1. You brought up screening and since it's the first step in immigration it logically follows that it's part of the reason for our success.
2. Why shouldn't the screening process be considered part of the immigration process? It is the first thing that happens when someone applies to immigrate to Canada isn't it? Seems pretty obvious tome hat it's part of the process.
3. That's not a fact, it's an unproven assertion on your part. Further your Swedish example is incorrect as well since the applicant, aside from being a refugee and not an immigrant, didn't make it past the screening process and therefore immigration and integration never even got off the ground. And in any case, we're talking about Canada not Sweden or any other country.

It's not about "lumping together" as you so crudely put it. It's about seeing the process as a series of steps which start, as you pointed out, with the screening process, and which finishes with the successful integration of the immigrant into society.