Exmuslim here:

Well Jihad is a physical/military struggle against oppressors of Muslims. Many Muslims view secular or liberal as a derogatory thing. Free speech would include the right to insult Muhammad.

Here is an authentic hadith or story about the Prophet that is related to insulting Muhammad. It is about a man who kills a woman who cursed Muhammad, and Muhammad says he doesn't need to pay any blood money for killing her.

“A blind man had a freed concubine (Umm walad) who used to insult the Prophet (peace and blessings of Allah be upon him) and say bad things about him. He told her not to do that but she did not stop, and he rebuked her but she did not heed him. One night, when she started to say bad things about the Prophet (peace and blessings of Allah be upon him) and insult him, he took a short sword or dagger, put it on her belly and pressed it and killed her. A child fell between her legs, and became covered by blood. The following morning that was mentioned to the Messenger of Allah (peace and blessings of Allah be upon him). He called the people together and said, “I ask by Allah the man who has done this action and I order him by my right over him that he should stand up.” The blind man stood up and said, “O Messenger of Allah, I am the one who did it; she used to insult you and say bad things about you. I forbade her, but she did not stop, and I rebuked her, but she did not give up her habit. I have two sons like pearls from her, and she was kind to me. Last night she began to insult you and say bad things about you. So I took a dagger, put it on her belly and pressed it till I killed her.” Thereupon the Prophet (peace and blessings of Allah be upon him) said: “Bear witness, there is no blood money due for her.”
(Classed as saheeh by al-Albaani in Saheeh Sunan Abi Dawood 4361).