Is it permissible to insult the people of innovation and confront them with it?

The questioner : ...

The Shaykh : Correct, this is a valid point. He, may Allah have mercy on him, says: How can he say that the ignorant ones insult them, when he himself insults them? He insulted them and described them, just a few lessons ago, as donkeys. Yes, and the Khawarij... among them are the filthiest and the most foul-smelling, and the lice come to be on their lips and teeth. Yes.
The answer to this is to say that what he means by confrontational insult is that which leads to fitnah (trial, discord or temptation). As for non-confrontational insult for the purpose of warning against them, there is nothing wrong with it. For this reason, when a man sought permission to enter upon the Prophet (peace and blessings be upon him), he said: So-and-so. He said: and he insulted him. But when he entered, he showed him kindness in his face. So he distinguished between facing someone and turning one's back to them, meaning that you insult a man to warn against his methodology, but if you insult him in his presence, you may provoke his anger, and he may insult the religion you are upon. Yes, is the reconciliation clear? Yes.