There are two types of people who make fun of Islam. There is one type who, no matter what they know about Islam, they hate it. You can never impress them or convince them. Even if the Prophet (pbuh) was living next door they still would hate it.
The other type are the ones who know nothing about Islam only the crazy behaviours which they see on the news and TV. They are not making fun of Islam, rather they are making fun of Muslims.
What is the difference with the enemies of Islam today and the enemies in the Prophets (pbuh) time? In the time of the Prophet he was standing up for truth and justice, he was standing up for the truth. They became enemies of Islam as Islam was standing for truth.
Today’s enemies hate Islam for different reasons. When one dog barks what effect does it have? None. We need to have the same attitude. When a dog barks what do you do? You leave it alone. When you answer them, they get louder.
When some people at the time of the Prophet (pbuh) insulted him by calling him a different name the sahabi (ra) just replied with “This is not the Prophet (pbuh)”. We need to adopt this behaviour. If someone says something insulting and untrue we reply with “This is not Islam”.