>more people will be peaked by the discontent it can sow,

I think this is sort of begging the question a bit, in the sense of assuming a specific conclusion is true when asking the question of whether it's true.

In particular, I don't think it's demonstrably true that immigration sows discontent. I do think that it can be shown based on the US example that far-right parties looking to sow discontent often scapegoat immigration as the cause for societal problems that may have nothing to do with immigration (like the classic "your cost of living has gone up coincidentally at the same time that corporate profits are at an all-time high and regulatory capture is widespread; it must be immigrants to blame for things being expensive!")