Existing immigration regulations allows only 5 categories that can be brought into the US by a citizen or relative:  (1) spouse (2)parent (3)brother or sister and (4) child (5) fiance.
Why discriminate against relatives from other countries who can bring in only 5 categories while relatives from the 6 Muslim countries can bring in - grandparents, grandchildren, brothers-in-law, sisters-in-law, aunts, uncles, nieces, nephews and cousins - practically the entire clan.