Even though some people think they are open-minded or enlightened, are they truthfully prejudiced?

People want to be quick to call a person a racist, bigot, homophobe etc. because they don’t agree on issues or positions, or are in opposition to something that goes against beliefs of highly visible groups that are supposedly marginalized or disadvantaged. In truth, when one thinks of it, if they are truly honest, they have prejudged someone by what they wore, their political party, neighborhood they lived in, profession they do or did, income, education, criminal record, if they are homeless or not, etc. How can you show me someone who is 100% open-minded and unbiased to everything?