This feature rewards high revenue Platinum Elites. Why shouldn't NW reward their high reveue loyal passegners? It may hurt some Silver or Gold Elites. for those who are panicking, don't. You need 1200 points to give away a Silver Elite Status. You get 1200 points by folowing activites:

Assuming one way trip gets you the spcified number of points:

15 OW or 7.5 RT in WBC
30 OW or 15 RT in diso****ed WBC
40 OW or 20 RT to Europe/Asia at Y/B fares
60 OW or 30 RT paid domestic F/P
120 OW or 60 RT in paid domestic Y/B
There are not many people who pay premium fares. The airline has every right to offer them incentives to attract revenue. It may improve finacial health of the airline.