I downvoted you for the edit saying that downvoters are being "PC and ridiculous".
If he is correct, then that is a valuable and interesting point to bring, and i would prefer to learn about it regardless of the words it is stated in. If he is incorrect, i would rather learn what the actual facts are. Downvoting him because he did not speak in a way you like is not conducive to learning in either way.
And before anyone accuses me of xenophobia, I think if we need their skills we should give them citizenship so they have the same rights, same mobility, and same negotiating power as the rest of us. If they don't have that parity, it lowers the bar for the entire market (citizen and resident alien).