We are all different. We like different things, believe in different things, like different kinds of people, settings, food, colors, clothes, everything.
It is common sense. We all know that. And many of the ways in which we are different doesn't bother us. If someone for example, told you they didn't like sushi, you wouldn't be offended. You wouldn't think any less of that person just because you like sushi. It wouldn't bother you. You would not seek vengeance or call them names behind their backs nor will you generate tremendous amount of hatred towards them because they don't like sushi.
But this begins to change when it comes to preferences in terms of beliefs. When someone chooses to believe in something you don't believe in: a religious concept, an ethical choice or even a social obligation our reaction becomes much more personal.
For some reason we gave ourselves the permission to decide for other people what they should be believing in and how they should be living. We took it upon us to decide what is best for someone else when we know nothing of what it is like to live as them. And when we find it in us to bite our tongues and grudgingly allow someone else to practice their own belief, we self rightously call ourselves "tolerant".
Human beings know, before belief systems what is right and what is wrong. Those are things that all human beings agree on: not to kill, not to steal, not to harm one another, not to lie, etc. Those are things that human beings feel bad doing anyway.
Beyond that point, who is the judge? Who assigned who to become the judge of other human beings? Why do we insist on shoving our own beliefs down somebody else's throat? And why do we choose specific parts of our belief system to defend so relentlessly and sometimes even violently?
I believe that belief systems that we try to force onto somebody else are belief systems we cannot force onto ourselves. We are insecure in our own belief and therefore project that insecurity by trying to control someone else.
If someone came up to you and said "human being have green skin", you would not invest a lot of yourself trying to convince them otherwise. You are so sure that humans do not have green skin that you find it ridiculous to try to convince someone else of something so obvious.
The same applies to your truth. If your faith, your codes of conduct, your life choices were so obviously right. If you were so sure of them that another person cannot stir any doubt or insecurities then you will not, for a moment, entertain the idea of trying to sell to someone else your own truth.
May we all recognize the power and beauty in the diversity of our truths.