This just seems like somebody dug up their father's "immigrants are stealing our jobs" "Immigrants are different" arguments. He even attempts to blame immigrants for the actions of greedy market driven capitalists. Is it the immigrants fault that they have the comparative advantage when it comes to the price of labor?
Economists agree that immigrants are just bowing to the will of the almighty market.
He attempts to make broad implications based on the actions of a small minority. RUN, THE MEXICANS ARE GOING TO SET UP DRUG PLANTATIONS!!! Not that you couldn't find ten thousand americans who would gladly work in Sequoia National Park, running a $150 million dollar drug-growing plantation and threatening backpackers.
Playing "Let's Blame the Immigrants" is a fun way to spend an afternoon. Anyone with a good mind for debate can paint any problem as being solely rooted in immigration. Lack of jobs? Immigration. Declining schools? Immigration. CEO corruption? Immigrants(they just seem to have this corrupting effect).
As for not assimilating promptly. I would guess that most immigrants don't really assimilate effectively. Their children seem to assimilate just fine. And their children's children are just your average americans.