The thing is, he can't really say that it's the best situation for him either. LA's lottery pick just two years ago is a power forward, the exact position that Simmons plays. Add to that a rookie head coach, some other questionable characters in that locker room, and some ball-dominant guards, and that's far from an ideal situation for the top rookie in the draft.
IN FACT, Boston is surrounded by high character players, in need of a starting power forward, has excellent management and ownership, and a top-5 coach in the NBA. Is there a better basketball situation for him than us at the moment? Sure, he won't get as gawdy of stats with us, but from a WINNING perspective we're his best option.
Philly is even a better option for him to maximize his stats, because there's virtually no offense on that team outside of Okafor and possibly Embiid.
So, yeah, other than the lifestyle and marketing opportunities, LA is not a good fit for him, which is troubling that he's dying to go there.