I suppose that's possible but I have looked closely @ several HHRs and they all have had the issue Except my2011 first one that I bought brand new.
Carefully looking again at this one I see or feel no sign of pitting.
I use only AC Delco Glass Cleaner on all windows with a Bounty Soft Paper Towel to clean them. If they are rather dirty, I wash them instead so as not to scratch the glass.
I also power wash the sides of the HHR before washing to get rid of the abrasive dirt and keep the wash pad clean.
The glass glides very smooth on the outside once cleaned.
None of my other Brand of vehicles has had this issue.
One thing that could be having an effect is the steep vertical angle of these windshields which is also and issue for the frequent rock damage.
I can only see it when the light is just right but then it is a real pain to look through.

SF

 

Had to replace the OE windshield in mine back in 2009, it had a crack, but was pitted also. Was told the glass is softer for safety. I still don't believe that line.

Replaced with a PPG with tinted/frosted top. That is still fine & dandy. So glad I got the tinted top one.