Oh, it's still possible that it was retaliation. For instance, airlines do it all the time. Two years ago, my wife and I were flying home from San Antonio. We boarded the plane, but the flight was delayed for a couple of hours. The captain made an announcement that there was a mechanical problem with the hydraulic system and let the passengers disembark the plane. The less than helpful airline staff at the airport directed everyone to the courtesy phones to make alternate arrangements. I explained to the service rep that it was absolutely imperative for me to get back to NY that night, due to the fact that I had to attend an important meeting at work the following morning. The service rep, who was actually very friendly and helpful, made arrangements for my wife and I to fly on a different airline. When we went to check in for the alternate flight, both of us were "randomly selected" for secondary screening. I didn't think much of it, until I read a rather interesting article on CNN a few months later. The article stated that it's common practice among airlines to tag passengers for secondary screening (by placing a special code on their boarding pass) for having the "audacity" to request alternate flights as a result of problems with their original flight.
The moral of the story is that it's quite possible that USCIS, as a large organization, can just as easily retaliate in a subtle way.