What you are asking for is for the Muslims to throw out the Sirah, hadiths and much of the Quran (in fact all of the Medina (later) verses of the Quran)
It's not possible
you must realize that the comparison is not JESUS and MOHAMMAD but for Muslims it is
They consider the Quran to be the eternal, uncreated Word of God (just as Christians consider this to be Jesus). So there can be no changing in any way as you can't change the Word of Allah.
I am sure at some level what you say is true. Many Muslims don’t examine that. They that they are simply good people. Some are. Many are not.
Some like the Alevi’s threw out what they found offensive and kept enough to keep the crazies from killing them. At some point that no longer worked and they had to run or be killed.