Those Sixers fans masquerading as Celtics fans won't want Philly to win this one , get too close to the Lakers and screw up their 25% shot at Simmons. 
Good (tommy) point
Technically if the season ended today, Philly would have a 33.8% chance at Simmons seeing as they can swap picks with the Kings and the Kings have the 5th worst record.
But I'm not sure how Philly winning this would have anything to do with the Lakers. Lakers aren't finishing with a worst record than Philly. Lakers need to lose all the games they can, because if they fall out of the top 3 (45% chance of happening right now), their pick goes to Philly... but it would be pretty surprising if the Lakers finished with a worst record than Philly this year.
What you're really trying to say is...
As a Celtic fan, we want Brooklyn to lose so the pick they owe us stays juicy.
As a Laker hater, we want Philly to lose so it hurts the Lakers chance of having the top draft odds.