Because the Clippers are better?
Right now, they are.
By the end of the season? Maybe not.
I think the Lakers have the better starters, even when PG returns, but the Clippers have the deeper bench and have had a lot less roster turnover.
Assuming everyone stays relatively healthy, once the Lakers get everyone on the same page, the gap should close considerably.
Barring some kind of big acquisition by the Lakers before the trade deadline, I expect that the Clippers will still be better, but the gap should be close enough that the Lakers have a good chance at beating them in a 7 games series. Especially since it'll essentially be 7 home games for them.