This is the easy way:
Foreigners come to country ->
Foreigners need jobs ->
Foreigners get jobs ->
Less jobs for nationals.
That's a very easy reasoning to following, it also gathers a lot of popularity, specially if I'm out of a job o with one I don't like.
Explaining why this is not true, or rather why it is much more complex than that, takes a lot of time, effort and understanding of non trivial economic concepts.
I would say the later is the hard way, this kind of reasoning applies to so many things that said by politicians all around the world to gather votes.
I would also like to clarify that I absolutely don't believe that that kind of reasoning is only used by the right wing politicians, that would be extremely naive.
Isn't precisely the problem that we can't have a rational discussion of this issue without people bringing out the X-word, the R-word, the I-word and others and calling for immediate stop of all criticism of the current situation?
The average Joe not being able to tell "racist" from "xenophobe" seems kind of trivial in comparison.