Parent discusses immigration in terms of xenophobia. The anecdote is an example of how an employee not wanting to be replaced by a lower salary individual isn't xenophobic. The desire to drive down wages though is in the economic interests of employers.
The anecdote would imply that if you're a tech worker, hiring more H1B's or outsourcing development is financially beneficial to shareholders and management while it puts downward pressure on wages for employees.
I wasn't one of the ones who posted in this thread, but the obvious answer seems to be that the person who is told "we'll replace you with a $10/hr worker from Pakistan" will conclude "immigration hurts me and should be reduced" and thus that political parties should adopt that position.
Neither political party in the US has this as part of their platform. I'm not sure whether or not anyone here is implying that they do, which is why I keep asking, to try to figure that out.