Why divert to LAX instead of going back to SFO? Is it just a scheduling thing, e.g., it would take longer to get a replacement plane to continue the flight from SFO than it would to fly to LAX and get a replacement there?
When combined with the need to burn off some of the fuel, LAX seems like a sensible choice. You don't need to travel over any particularly tall terrain, LAX is large and should have sufficient runways for an airplane that might have trouble coming to a stop quickly. Since there was no issue with actual in-flight operation of the airplane, it's also not a 'land right the frak now' situation.
And then there’s a potential bias against SFO, given they just let an airplane take off that HAD A WHEEL FALL OFF. Maybe they aren’t the best party to examine the plane just now.
https://www.mroglobal-online.com/companies/united-technical/