The definition of bias given in the article is, I believe, quite different from the definition accepted here. LW/OB largely thinks "bias" means inaccurate opinion, not socially unacceptable opinion. There's no natural law saying negative opinions or pre-formed opinions are always inaccurate. But they often are, especially when we're thinking about clumps of people different from "us".

Now for my personal answers to your questions, that may or may not be shared by others here. Yes, you should keep the capability to be biased if you want to function more efficiently. Yes, you should hide it for signaling reasons. Yes, you should take into account the irrationality of other people's biases and reduce your own biases to an evidentially justified level of negative (or positive) "stereotype", but no closer to "neutrality".