At the risk of being dead wrong: the San Diego Chargers don't want to move to Los Angeles. They don't even really care if another team moves to Los Angeles. What they do care about is two teams moving to Los Angeles, which explains all of this Carson stadium hub-bub.
Basically, if one team moves to LA... no harm, no foul. The Chargers can survive such a market and probably keep a lot of their Orange County support.
If two teams move to LA, however, the Chargers lose a ton of upside. So, in that case, the Chargers will insist on being the second team.
But, if they can get a promise from the NFL that Los Angeles will be a one-team city (as it should be), then the San Diego ownership will calm down a bit.
Anyway, that's that. We'll see if I'm right.