See the thing is quoting studies and statistics doesn't matter a damn to people in that situation and personally I don't really blame them.

Here is an example I know happened 4-5 years ago, I work in the north east, small town with a lot of fairly high profile factories (I'd wager more than a quarter of the town works on the industrial estate, including myself).

One of the local factories does a lot of winter seasonal temp work (4-6 months of the year, and traditionally lined up quite well with another factory that usually had extra work in the summer) I knew a lot of people who had bounced between the 2 for years.

Anyway that winter the company decided to hire like 50 odd-polish workers (out of maybe 250 seasonal workers) they were put up in rented houses (often 6-8 to a 3 bedroom house), hired for a fixed 4 months and then they'd go back home (if they chose, most did).
Well as you can imagine that didn't go down well, that's 50-odd locals who lost their christmas jobs to poles.

A guy I knew killed himself that christmas - he was one of the ones who didn't get the job after getting the job 7 years in a row and was very vocally angry in one of the local working men's clubs about it. So naturally a lot of blame for his death was aimed at the company and immigrant workers. He wasn't a bad guy, no real issues (drug/drink etc) but not the brightest of guys and zero education to speak of.
Average enough worker, what we call a "steady-away" kind of guy.

That kind of thing poisons entire communities against immigrant workers.

Now I don't for a second blame the polish workers, but the company decided that year it was cheaper for them to arrange with an agency an easy 50 workers than go through their usual hiring process - they never did it again (so far anyway) due to the massive negative community feedback.

It's easy to try and bring up matters of average hourly rate, and studies percentage dips over X years - but that doesn't mean a damn to small communities that have been negatively impacted. Even if it's only a tiny fraction (50 odd "lost" jobs out of maybe 8000 jobs in that industrial estate) of that community that was actually hurt by it.