I have always felt very strongly that when a person has mental illness, their mental illness combines with personality; their mental illness is not their personality. The two combine and form a result.

For example, my last severely delusional episode sent me on a quest to try to save all the homeless people in California. I arrived at the LA airport with no shoes (they broke on the plane), a giant first aid kit and the sheer determination of intense bipolar delusion. And off I went. Makes sense to me in retrospect, because prior to the episode, I had been researching homelessness in the U.S. My delusions tend to draw on something recent when they happen.

If someone is extremely hateful and prejudiced, and can normally blend in with society, and then have say, a severe mixed episode, their delusions are likely going to draw on their natural personality and thoughts to at least some extent. The only role bipolar disorder would play, is taking their natural self and sending it spiraling out of control.