First of all, it is not good to mock someone lest you can hurt him in the process along with others. Humans live in society, not in jungle. Everyone should be careful to other not to harm him in any way. At least this is the teaching of Islam. The Prophet Muhammad peace be upon him said, Muslim is that person from whose mouth and hands others are safe.
So, in this regard, you cannot harm anyone with your bad saying and bad deed.
There are lots of good teachings of Islam which is nothing but to make the peace prevail in the society. You can read them in Islamic books or ask Muslim Imams in mosque near you.
Now about the video, what is the benefit of this video if someone can tell me? Muslim love their prophet and they should be allowed to live with that. It is unfortunate that Jesus is not loved by christians as much. But Jesus peace be upon him is our prophet too who came 500 years before Muhammad. Muslims believe in him too being a prophet otherwise he can't be a Muslim.
There is a complete chapter in the Quran name 'Chapter Mary' named after the name of the mother of Jesus peace be upon him. Muslims never mock him cause he is loved by them. Mocking him would mean exiting from Islam.
So, it is indeed a big deal. Let the peace be prevail and let everyone be happy with their things.
