Undead=Evil

[willpell]

Set aside morality for a second.

You have two sides, one wears black hats the other white. They hate each other and do awful things to each other simply because they are in conflict.

While I personally disagree that there is not a correspondence between morality and alignment (it may not be an exact correspondence, but I still consider it a strong one), I like this way of putting the point. It also makes me think, with some amusement, that Law and Chaos are those two guys from a Star Trek episode which are white on one side and black on the other and are trying to kill each other because they're colored on the "wrong" sides.

(It's very aggravating that the plane of Acheron is Lawful-aligned, because it seems like exactly where this sort of endless, idiotic battle should take place. While the 'I'm right and you're wrong, so shut up' mentality is pretty much Lawful and thus Acheron's status as a Law plane is quite thoroughly valid, it still seems as though a Neutral version of the plane of never-ending battle would be just the place for a bunch of Skarn and Rilkan Incarnates or something to duke it out for all of eternity.)

This then becomes a really subjective view of alignment. A vampire who sees humanity as cattle is no more evil that a human who sees cows as cattle unless you happen to be a human or a cow.

The problem with that reasoning (not meaning yours, as this is a pretty common attitude that gets voiced in conversations like this) is that there's really no sensible reason why a vampire should see humans as cattle. Vampires used to be humans, they presumably at least partially remember what it was like; vampires can talk to humans, humans can talk to vampires, the two can debate philosophy for ten solid years if necessary, and even if we assume centuries-old vampires experience an extreme form of time dilation, I find it dubious at best to believe that this alone suffices for an otherwise reasonable vampire to dismiss humans as no more than animals. (That vampires as portrayed in D&D are not even close to "reasonable" is a separate issue.) With something like mind flayers, or a genuine Cthulhoid entity, or even the gods, you can justify the "they're just dumb animal, ignore their meaningless noises and get on with your meal" attitude; such beings are functioning on an entirely different level. Vampires, though, are still speaking Common, and so are humans, so I can't really find it in myself to believe that they have any sensible non-Evil basis for a cultural attitude that dismisses humans as food and nothing more.

Objectively if we measure good and evil as the weal or woe of an action then slavery results in greater harm that good for the majority, as does the killing of humans to keep the vampire alive. They are objectively evil acts.

Now this part, on the other hand, I would say is debatable. Ignoring for the moment the +8 level adjustment on the vampire template, if we assume that vampires continue leveling at about the same speed as humans throughout their substantially longer lifespans, and that they can go into epic levels or even triple digits given enough time, which they are...what they become capable of accomplishing gets into the realm of literally godlike power, and I can see a very sensible argument that says a civic-minded vampire with 47 Wizard levels can accomplish more good than all the people he eats, combined, could hope to achieve in their entire lives. He could very justifiably claim, on the basis of his public works, to be the foundation of his entire society, and as much worthy of protection as any of our world's holy books or institutions of law or bodies of science or anything like that. For him to get inevitably slapped with the evil-stick, even in the event that he is an immortal Gahndi-Lincoln-ChuckNorris-etc., who makes life better for millions of people for 8 hours every day and then eats a dozen or so of them for the next 8 hours before going to bed...well, hopefully my point can be vaguely glimpsed in this cloud of words I've exhaled here. (Sorry, it's late enough in the by-my-standards-evening that my command of sentence structure is beginning to gain the Incorporeal subtype.)