How can I be so arrogant to judge someone?

If those who claim to know the truth better start to label others as heretics or cults, and persecute them and make every effort to destroy them -- this is ugly.

What if those who claim to know the absolute truth start to label others as heretics, and persecute them and make every effort to malign them -- this is uglier.

That would involve much higher arrogance of "I know the absolute truth, which you don't." However, sad to say, the nature of human being cannot change overnight, and this thing keeps happening again and again. It is a sad thing because when you are performing this type of arrogance, you would not find peace and happiness in yourself, and nor God feels joy looking at you. This is an action of creating hell around you, which your conscience would know.

But, what is more fearful is that I have to admit that's exactly what I am doing!