I have read that he just fought in the war because he was a German patriot, I have also read that he fought because he was a Nazi, and believed in the cause.
For this question, I would suggest reading this thread by /u/commiespaceinvader where he tackles the problematic aspects of Rommel. In short, Rommel was a very morally compromised figure even though Rommel had the benefit of fighting in theaters that did not have the same level of war crimes as the Eastern front or the Balkans.