I'm a Skylord myself, and I have not seen rank discrimination. I would never do it myself, and almost all of the ranks help, or hang out with the people with non ranks. Personally, I have no preference as I never see it happen.
Lol. Actually i think, that donors are discriminated also. Look at the donor400 people saying how bad any donor below is. Or look into the chat. Some donors really get punished by other donors. And i trapped myself discriminating a donor. I extra wanted a chest trade, because in case he tries to scam me, the most people would trust the donor more than me and i would lose my items. I think that non donors also have some bad donor stereotypes.