Why does Blasphemy destroy undead which are generally evil?

Question

I was reading the spell Blasphemy and its got contradictory texts/

Its area for example says

Area nonevil creatures in a 40-ft.-radius spread centered on you

Then the spell effects

Killed: Living creatures die. Undead creatures are destroyed. Save negates. If the save is successful, the creature instead takes 3d6 points of damage + 1 point per caster level (maximum +25).

The subtype page for undead clearly mentions they are evil (howeve there is one case that is not evil, but juju undead are not part of this question)

Undead are invariably evil, as are the means to create such beings.

So since the spell isnt supposed to hurt evil things, why are undead destroyed?

Answer 1

Because it's possible for undead to be of non-evil alignment

While it is true that undead, in general, are all of evil alignment, that is a general rule, and as such, exceptions are allowed. For instance, Ghosts can be of any alignment, even Lawful Good (example).

A shadowdancer's shadow companion will match the character's alignment:

Unlike a normal shadow, this shadow’s alignment matches that of the shadowdancer, and the creature cannot create spawn.

It is also possible for any undead to become non-evil if they happen to wear a Helm of Opposite Alignment.

But before Pathfinder existed, there were non-evil undead as well, in Forgotten Realms we had the Baelnorn, elven liches of non-evil alignment (mostly lawful neutral or lawful good).

As such, that line is there to handle these special cases.

Answer 2

Blasphemy does nothing to evil creatures—living or undead. It only affects non-evil creatures. Just as “Living creatures die,” applies only to those living creatures that the spell affects, that is, non-evil ones, “Undead creatures are destroyed,” applies only to those undead creatures that are affected in the first place, which again are the non-evil ones. Which is a rare thing for the undead but not actually impossible—and even if it was, a future exception could always be written, so blasphemy should account for that.