When a proud sinner is confronted with their sin through the 10 commandments a battle is started in their heart and mind. Their conscience is convicting them of their sin while their mind is fighting to hold on to the belief that they are a "good" person. What results is anger. You've heard the saying, "Don't shoot the messenger for the message"? Well, this is what is happening. A proud sinner will lash out at the one who brought the message.
"Don't push your religion on me!" Have you heard this? It's the messenger being "shot". It is also proof that that person is being worked over by their conscience. Why else would they respond so harshly? You won't see the same response if someone stood up in the town square declaring the sky to be red and to repent of our notions of a blue sky. "Repent, blue sky believers!" No, you aren't going to hear anyone say, "Don't push your red sky belief on me!" You won't because that message doesn't convict the hearers' conscience. People would regard it as foolishness and not give it a second thought. But those who are being confronted by their sin are bothered, those who aren't don't give it a second thought because it is foolishness to them.
This brings me to the other question, "Why does the gospel rub people the wrong way?" Check out 1 Cor 1:18....
For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God. 19For it is written: "I will destroy the wisdom of the wise; the intelligence of the intelligent I will frustrate."A man dying on the cross for me? That is silly. Tell a sinner that before they are convinced of their sin and you've just turned the gospel message into just an ordinary event in history. It takes seeing that one is a sinner before hell and the cross make sense. For ways to biblically witness to someone go to The Way of the Master.