Summary You are not a bigot. You are a creature created by instinct. Trust your gut and perfect your internal heuristic map of the world.

Body

This planet is home to 7+ Billion humans. In your lifetime, you are likely to meet almost 20,000 of them. This is terrible news, because as you may remember, you are a hairless monkey with limited storage space.

For 30 years, we have been told that everyone is a unique and special individual, and that to judge people based on appearances is bigoted and ignorant. This makes for good rhetoric, and drum circles, but the reality is (as usual) a little more complicated.

How can you, one man against the world build a strong internal data set to help you categorize people, and generally make sense of the world around you?

Enter: Heuristics

Heuristics are a "good enough" set of rules to help you mentally map your reality. If your heuristic set is strong, then you can make sense of a huge amount of data much more easily by making general assumptions based on correlated traits.

Your brain is the most advanced piece of data processing hardware on the planet, but the catch is that it you are really only consciously aware of a few operations at a time. Your brain is smarter than you.

Let's work through some examples:

Example 1:

Knucklehead #1 is an adamantly open minded, nonjudgmental, individual. Although he personally has experienced unnecessarily cruel punishment at the hands of several ex-girlfriends, he is committed to bringing zero pre-conceived notions to his new relationship. He constantly battles an internal dialogue that attempts to draw potential outcomes from his new girlfriend, and her girls-night every-night adventures.

Knucklehead #2 has accepted himself for the imperfect shitlord he is and embraces his internal prediction engine. His gut tells him that even though it is not causal, a good enough corollary relationship exists between girls that drink six nights a week and girls that suck dick through holes in the men's room wall, that he should prepare himself for the eventuality of his unicorn chugging dong. This isn't bitter sexism, it's Heuristcs.

Example 2:

Like their American counterparts, the Israeli government imposes strict rules around air travel. Unlike their American counterparts, the first priority of these security agencies is results. Tasked with preventing terrorists from boarding planes, they did some homework, and realized that the vast, vast majority of terrorism was at the hands of muslim extremists. So, they stop WAY more dudes that look muslim-esque, and almost zero toddlers in onesies. This is not racism, it's Heuristics.

Conclusion/Lessons

I know that you have heard your pops, grandfather, or stepdad or auto mechanic or whatever other masculine male you look up to mention his "Gut Feeling". Are you in touch with your gut feeling? Your gut feeling is likely the brain's incredible subconscious background processing of HUGE data sets, honed over millennia of evolution to give you the best chance at survival.

Never beat yourself up for your ability to make assumptions based on broad data. It's the reason you're alive and the best chance you have at staying that way. Beef up your heuristics brother.

Sources:

https://www.interaction-design.org/literature/book/the-glossary-of-human-computer-interaction/heuristics-and-heuristic-evaluation

http://www.psych-it.com.au/Psychlopedia/article.asp?id=53

Further reading:

http://www.livescience.com/46411-free-will-is-background-noise.html

https://en.wikipedia.org/wiki/Heuristic

http://www.livescience.com/12916-10-facts-human-brain.html