Polarity. Binaries. As humans, we're drawn to them, because they make the world easier to understand. They take the work out of classifying what we encounter in life.
If you're not with us, then you're against us.
If you're not perfect, then you're a failure.
If you're not straight, then you're gay.
If you're not gay, then you're straight.
If you're not male, then you're female.
If it's not perfectly good, then it's utterly evil.
If the answer isn't no, then it must be yes.
If it's not a scientifically proven fact, then it's a horrendous lie.
If it's not so clean it's sterile, then it's totally filthy.
If you're not a virgin, then you're a whore.
If you're not monogamous, then you have no loyalty or ability to love.
If you're not a scientist/doctor, then you're stupid and ignorant.
If you're not a layperson, then you can't understand what real life is like.
If you're not a size 0, then you're fat.
Look at those statements carefully. Anyone who can't see that there's a deep, common conceptual problem with each and every one of those statements should stop reading now.
In real life, there are few, if any, true natural binaries. All of these heavily polarized binaries are human inventions, human concepts. Even Alive vs Not Alive is a gradient - viruses are so hard to categorize because they straddle the barrier. We classify them as "not alive," but they haunt us, because they have so many of the characteristics we use to describe "alive." The barrier, the cut-off point is completely, humanly arbitrary.
So are all of the binaries I listed above. Each is a gradient, not just shades of gray but a glorious field of color. We have artificially created binary categories to define them because it makes it easier for our poor little brains. Sometimes, that's a good thing (for example, "food" vs "not food" was incredibly adaptive from day one); other times, it is horribly damaging.
How many times has "if you're not with us, then you're against us" been used as justification for hatred, violence, subjugation, exclusion?
How many bisexual people have found that they aren't welcome in many gay communities?
How many transpeople have found themselves unable to find acceptance at either pole of the gender spectrum?
How many non-monogamous parents have had their children taken away?
How many spiritual or philosophical truths have been laughed away simply because they cannot be tested?
How many people give up, or never even try, because because they cannot be perfect?
How many wonderful accomplishments are ignored or even reviled because they are not perfection?
How many good people find their lives destroyed because they made a single mistake, and were identified only by that mistake for the rest of their lives?
The answer is not to destroy all classification systems, all binaries and categories and labels. We're human, we need them - that's just how the brain works. The answer is to be aware of your binaries and your biases, your categories and your labels. The answer is to question them. How are they helpful? How are they hurtful? Why are they there? What does it mean to me? Do I really need it in order to function? When you find ones that are more healthy than hurtful, keep them, but always under surveillance. When you find ones that are harmful, try to understand them, and to perceive the gradient of color that lies between and around the poles.
Dare yourself to look inside, and to be honest with what you find. No one is perfect. No one can eliminate all of their false binaries and biases and stereotypes. That's not the point. The point is the awareness, the attempt.