Two differences between Letsrun and TFN, as I see it:
Letsrun has as much space as they want so it wouldn't take much at all to include results, or a link at the least, while it does cost TFN for each additional page they include in their magazine.
Letsrun doesn't have to care because this board isn't dependant on subscriptions. TFN does rely on subscriptions and their advertising dollars are determined by the number of readers. So, if people interested in NAIA results let TFN know that they and those they know will end their subscriptions if they don't include at least NAIA National results, they will either include them and save readership, or ignore them and lose readership. I'm sure NAIA runners, coaches, and fans would make some impact on their subscription base if they acted.
That's pretty much your recourse with TFN. End of story.