The following is out-of-character for obvious reasons.
Now, I'm probably not the best person to answer this question as my skills of persuasion are limited at best, but I'll try to summarize the deal.
I can't speak for the Order, but most of our characters believe that humans are in fact the superior race - in case you've been informed otherwise, Tanith is a servant and a cook. She's servile, meek and far below us in terms of authority.
Now we've got that out of the way, I'm going to have to give you my old rant.
There is nothing I hate more than people who use their modern-day standards and morals and apply them to their characters. We live in a fairly politically-correct, sheltered world and almost all of us would consider real-life racism, violent activity and religious zealotry to be bad.
But for your character to have the very same opinions? That's not only boring but I would call it bad roleplay. And that's what I, personally, have experienced from every single dark elf roleplayer I have ever come across with the exception of Tanith and Princess Sythra Duskwind. Quite simply, to me they all seem to act the same way - edgy, free-spirited, anti-authority, confrontational, anti-racism, open-minded, liberal and anti-conservative.
My character doesn't need a reason or a provocation to hate dark elves, he just considers them below him. If your character does not act deferent enough, you'll be subject to the 'racism' and the hatred from our characters.