Why are people so easily offended by differing opinions?

Why are people so easily offended by differing opinions?
It's seems that whenever my opinion is different from someone else's they are instantly biased.
Why is that?
On some of my mytakes I've been getting some hate.
How do I make my opinion less "in your face" I guess?
So people will respond better to mytakes.
I'm tired of people constantly judging me for my opinion that I'm entitled to.
Is it the way I'm writing that makes them so angry?
Why are people so easily offended by differing opinions?
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