I've noticed that as well and its the same for business class awards. The other carriers that got HND routes also have a bunch of award space.

It makes sense- there's less connecting traffic through HND- people who want to go LAX to SIN can't easily connect easily via HND. Also, since the flights were loaded recently, they've had less time to sell revenue seats vs a Narita flight thats been selling all year. Low level awards are a function of whether Delta thinks they will sell every seat on the plane...they are obviously betting in the short term that they won't so they've released a bunch of low level awards- I guess 60,000 miles is better than nothing!