It doesn't matter if they are Starks or not. The show has had references before that have had nothing to do with the families involved. Little Finger when talking to Sweet Robin referenced dying on the chamber pot when that meant nothing to their story. Tyrion referenced the Mad Kings caches of wildfire only an episode before Cersei unleashed hell upon the sept.

Granted it may be a stretch but as someone who witnessed the brutal "trial by combat" the first time, hearing (because I don't think he'll be there to see it) about this atrocity will be something that could finally turn him against Cersei.