Summary:  Sometimes a Presuppositional Defense is used to defend Muhammad's actions and sayings.  
1.  A Muslim presuppositionalist assumes that all of the sayings and actions of Muhammad must be good.  
2.  Thus, any unfavorable historical record about Muhammad is automatically rejected as a false report, because the initial assumptions do not allow for any negative historical evidence.
3.  However, a Muslim presuppositionalist is not willing to grant the presuppositions of a non-Muslim.  This is intellectual hypocrisy. 
4. Epistemological hypocrisy is a special problem for Muslims who live in an Islamic country.  In these countries, there is freedom to critique non-Muslim religions, but Muhammad's sayings and behavior cannot be criticized without fearing the charge of blasphemy and the sentence of death.

An Example

Narrated Anas bin Malik: "A man peeped into a room of the Prophet. The Prophet stood up, holding an arrow head. It is as if I am just looking at him, trying to stab the man."
Sahih Al-Bukhari Volume 8, Book 74, Number 259.

The Most Exalted Character does not accord with this behaviour, especially from the Prophet of Mercy who was affectionate and compassionate to the believers. It would be assumed that the Prophet would go to this man who had peeped into his room and would teach him Islamic conduct and make him understand that what he did was forbidden. Not to take an arrowhead and attempt to stab him and poke his eyes. Probably the man could have meant well for the room was not his wives' room. The proof of this is that Anas Malik was present in it. What a great accusation this is against the Prophet of Allah; as it portrays him as an ill-mannered and hard hearted person who attacks a person without warning, i.e., assaults the man so as to take out his eye.

Critique

Presuppositionalism assumes an idea to be true. And, with this beginning assumption, it judges the truth or falsity of other claims according to their correspondence with the initial assumptions.

In the example above, the presupposition is that Muhammad was a Prophet of mercy who was always affectionate and compassionate to believers. It assumes that he was never an ill-mannered nor a hard hearted person who would attack without first giving instruction.

Of course, if one begins with a set of unquestioned assumptions, then one must reject all evidence to the contrary. If the initial assumptions were that Muhammad was always merciful and compassionate, then it could never be the case that Muhammad was angered and desirous to poke a believer’s eye out. It has to be rejected because the initial assumptions don’t allow this possibility to have ever occurred. The idea that such an event could have actually occurred is never entertained in the mind of the religious presuppositionalist.

Presuppositionalism is a form of fideism, and it protects the religious belief system from the harsh realities of actual historical events. Because, if a Muslim were to accept that Muhammad desired to poke the person’s eye out, then the Muslim's presuppositional foundation would be destroyed. It would bring into question the Muslim’s preconceived ideas about Muhammad's character. And, if these preconceived ideas were to be discarded, perhaps, then Muhammad’s claim to prophethood would be less certain. This rarely happens because the believer finds great comfort and assurance in presuppositional beliefs.

So, the above hadith is rejected—not on historical grounds—, but it is rejected because it does not accord with the believer’s assumptions about the character of Muhammad.

There is the additional problem that two contradictory presuppositional belief systems cannot be adjudicated on presuppositional grounds. One side assumes that their belief is true and the other side assumes a contrary belief to be true. No matter how much historical evidence either side gathers, the other side rejects the historical evidence, because its presuppositions don’t allow any contrary evidence to be admitted that would challenge their initial presuppositions.

Sometimes, presuppositionalists engage in intellectual (epistemological) hypocrisy. Being presuppositionalists, they are not eager to allow their assumptions to be challenged, but they are eager and willing to challenge the presuppositions of those who have a different religion. When they challenge another religion, they are not willing to grant the presuppositions of other religions.  They argue with the opponent as if historical evidence were necessary to establish the claims of their opponent's religion. But, they are not willing to submit their own religion to the challenge of empirical historical evidence.

Epistemological hypocrisy is a special problem for a Muslim who lives in an Islamic country. In such countries, a Muslim may freely criticize all religions except Muhammad’s religion. Because, if a Muslim were to criticize the sayings or behavior of Muhammad, the country’s Islamic leadership could charged him with blasphemy and call for his public execution. So, for a Muslim, no matter what Muhammad said or did, it must never be criticized or become a reason to question his prophethood. In some Islamic countries, it is safer to be a hypocrite than be an honest thinker. Because, embracing the historical evidence could be a threat to a person's life.