It often seems that when a non-LDS football player is a starter (or even earns above avg productivity as a backup), they are instantly one of the top "fan favorites." & I have no proof here so take it FWIW; but on more than 1 occasion ive wondered if that happens because of their religious status. Whether its a hope to eliminate any possibility that player doesn't feel 100% part of the family..or maybe some subconsciously think a non member player being so popular might bring in more like him in the future. AGAIN total opinion.
Relating this to the OP, maybe non LDS players dont have as many non football "social pressures" like getting married asap or even worrying about even small mistakes in public that u might be judged on. This along with maybe being over exuberantly loved might just help some not worry so much and add confidence so they feel like a superstar and play like one. IM PROBABLY TOTALLY OFF BASE AND THINKING OUT LOUD