Because nice people can't argue!
If you all want 100% nice people, go somewhere else. Like, really far away. I've never even met someone 100% nice (Mage comes close).
No one is completely "nice". It is mostly a speculative thing, an external measurement. What is genuine may be interpretted as sarcastic and what is kind may be seen as manipulative. But besides that, internally, there is no man who hasn't spoken or acted out of anger, pain, or sorrow in a rude, unjust, or unreasonable way. Anger is a natural emotion. Sadness is a natural emotion. What mostly matters is that you use and express them in a healthy way. :o
Plus there are a number of views that go into this - levels of how mean or kind something is that all can be seen in a number of lights; As such, just because someone acts mean doesn't mean they are a bad person. And likewise if a person does something kindly that doesn't define them as a saint. People are very...odd and diverse. By that, I find it best to give the benefit of the doubt to them and treat them with respect, kindness, and Love, as I'm sure many others do the same.
And Narko, it isn't nice to swear. :U