it is not a reflection on the quality, or lack thereof, of the car. It probably came out of the bumper. Car manufacturers, including Subaru, use styrofoam in the bumpers as a shock/energy absorber. It is ideal for that role. It does a great job of maintaining its shape and size unless it is crushed during an accident. It absorbs some of the energy from the impact, just like a shock absorber would. Under light impact, it will return to its original shape. As mentioned above, a heavier impact will crush it.
Reference the following note cut and pasted from a Subaru repair site:

The styrofoam component of a Subaru bumper is an energy absorber that is usually made of a type of polystyrene or other durable material. The foam is placed between the bumper impact bar and the bumper face bar.