The argument for that is that Subarus are designed with a long travel suspension that need the full travel to work properly. It is a "rallyesque" type suspension to absorb all bumps while handling corners. If you've ever driven hard on a mountain road with lots of off camber turns and bumps midturns you'll be able to appreciate the work that Subaru has done.
But, for most types of driving lowering the car will always garner "better" handling due to the lower center of gravity. As long as you don't go too overboard you'll be fine.