If there are uses of negative energy that are not Evil, that is directly contradictory with Animate Dead being Evil because its use of negative energy causes pollution. If you can summon a being that is literally made of negative energy without causing problems, I fail to see how it is remotely possible that making something that is simply powered by negative energy would have to be Evil.
The RAW is simply incoherent. This is a more reasonable discussion of negative energy, but obviously not RAW (since the RAW doesn't make any sense).