What is the ruling on insulting the Islamic preacher Amr Khaled? Should one shun a person who insults him, mocks religion in jest, and refuses to stop doing so?

Cursing the religion is apostasy, whether in jest or not. It is not surprising for someone who curses the religion to curse some of those who practice it or to mock those who advise him. The prophets were harmed, disbelieved, and mocked. Therefore, adhere to your religion, avoid sitting with people of falsehood, seek righteous companionship that helps you do good, frequently supplicate for those who have deviated, and use beneficial means to guide them.