Most of what I've seen in this thread (believe me, I didn't read the whole thing), seems to be a boiler-plate argument between the Freddie N's and the JC's. If, of course, you ascribe to the merits of "Relativism" you can wash away milleia worth of Dogma
and logical thought and claim that everyone is correct, and no one group or faction can be more or less right than any other
As for the rules of Holy/Unholy magic.... Raising the dead is not necessarily a nefarious act. It is quite possible that the dead
want to come back and serve a/the god. Obviously, those who raise the dead will want their followers to believe it righteous and those who do not will desire their followers to believe it blasphemous (Relativism raises it's ugly head oncemore). It is best to simply consider them empirically rather than using the connotation of their naming. We shall call "Holy" magic "Living" magic and Unholy, "Dead". Races that lean toward "Living" sacred units will be more thematically suited to "Holy" magic while those who tend toward "Dead" units or who require additional (low-rank) troops to flesh out their ranks will be benefitted more by "Unholy" magic.
If we examine the traits of blood magic, we find that it includes no sacred units, 3 types of undead units, and most of it's units have high morale, but are generally lower in population than say...Nature. Thusly, Blood magic finds its niche with "Unholy" because of a) little need for Courage magic, b) no need for Blessings on non-undead units, c) a need for rank-and-file troops (not, really, but one could make an argument), and d) an interest in using the general undead "buff" spells for vampires/bone fiends.
Thus, Blood magic is both empirically
and thematically suited for Unholy