Because that, in itself, will create imbalance in the world and will likely contribute to Fellden's downfall. Temperance is a problem because she is being resurrected now and by a group that is dangerous enough to allow innocents to die in order to restore some twisted version of balance.

That isn't her fault.

[ Though it sounds like even Death wasn't very pleased with her, and Azrail certainly hadn't seemed impressed. ]

If she was being revived by a different group or under natural means, this likely wouldn't be as much of a problem.