> "Social cohesion" doesn't come up, it's not an issue.
Again, asserted, no evidence, no argument. Social cohesion is absolutely an issue. We feel it when we have no community organizations, don't know our neighbours, and have nothing gluing us to where we live. The famous Putnam study on social capital is a fine piece of evidence here.
I believe we can surmount Putnam's identified problems, but only if we have a rate of influx that is sustainable. That means each newcomer has a chance to get proper language training, recertification, and actually integrate into a local community, which I'll somewhat arbitrarily define as having made some real friends out of the group of local or fully-assimilated people. This is the core requirement of being able to fully participate in social life.
> The wealth and income inequality in Canada is much lower than in the US.
Some of us would like it to stay that way, and we understand that bringing in a whole bunch of people to undercut the price of labour while eroding our hard-fought social capital is not the way to do that.