The epiphany is as follows:
1. There are a lot of people with very negative views of corporations roaming around the internet
2. http://en.wikipedia.org/wiki/Confirmation_bias will cause them to view goodhearted actions in a negative light, and genuinely think they're right
3. Therefore an important goal of PR is to include falsification ammunition alongside announcements that are likely to be misunderstood
Less abstract breakdown:
It's pretty clear that most people would prefer a car that instead of just saying "please find someone to fix my xyz" says "please find someone to fix my xyz, and fyi Foo Dealership will likely be the most convenient" -- maybe my friends and I are just lazier than average, but that actually sounds great for me, and I could see several friends really appreciate not having to spend the time picking out a repair shop. This is especially true if they handle figuring out who is certified to do warranty covered repair work.
So GM likely thinks of this sort of application as a small to medium win: GM cars are somewhat less hassle to own, and maybe last a bit longer on average / get a higher average resell value because people are getting things repaired sooner rather than later.
However, because people will think "oh, they're just doing it for the sale" (which they are in this case, just not the one-shot-sale but instead the generations long brand building approach), GM should announce both at the same time, and include a few points that obviously invalidate the fly-by-night opinion -- Do they recommend places based on Yelp reviews + distance? Do they even take money from repair shops when recommending? Do they use wait times and the urgency of the repair as the primary criteria?
Basically if GM included some answers to questions like the above as ammunition, then when journalists / analysts / online message board readers get in to arguments about this question, GM is significantly less likely to come out looking evil.