Not the point. The point of the playoff is to have the best teams. It's not "we should have put X, Y, or Z in because they would have beat SLU", it's "we should have put X, Y, or Z in because they are better than FAMU"
The point of the playoffs is to take the best representation of each league from around the country. The Big Sky, CAA and MVFC are plenty well represented with zero chance of their best teams being left out. Jackson State beat FAMU by one-point, 7-6. There's plenty of argument to be made that FAMU is at least equal to JSU as the best representative of the SWAC. Furthermore, they went 9-2 with a respectable FBS loss. They earned their way in and lost, just like UNI did, Davidson, Missouri State, etc. To follow your line of argument, Nicholls State should have been in — they are a lot better than several teams who did get in.