Islam makes it very difficult for a Muslim to convert to Christianity, as Islam raises the bar on several important matters.
Islam raises the bar on verifying the historical authenticity of religiously authoritative statements, while Christians are comfortable taking from scriptures whose sources are not scrupulously verified.
Islam raises the bar on scriptural preservation, while Christians are comfortable admitting that they do not have to settle for 100% scriptural preservation.
Islam raises the bar on clarity of fundamental doctrines (5 pillars of Islam + 6 articles of Iman), yet Christians need to struggle hard to demonstrate that their Bible teaches the most fundamental belief of theirs like the Trinity. Imagine if Muslims had to produce hundreds of books and tens of thousands of articles to prove that Islam teaches the Shahadah. That would be pretty outrageous and mindboggling, no?
Islam raises the bar on scriptural infallibility, while many Christians are open to Biblical errancy and try to suggest new creative ways of understanding the “inspiration” of the Bible’s authors.
It is extremely difficult for a Muslim who has been used to such standards to settle for less and consider Christianity. People strive to gain more, not compromise to settle for less.
When Christians ask us to “consistently” evaluate their faith as we do ours, they need to understand that such a request is not in their best interests!!!
The hard problem of the will: expending intellectual energies in simplifying dissonance rather than seeking recourse from ambiguity.
On point number 4: it's unfortunate that this is basically described the "aqeedah wars". It's just hundreds of books debating the sifaat instead of the shahadah. The difference with Christianity is that sifaat is فرع and shahadah is أصل , but that goes to show the error people make in treating this issue as though it were أصل.
Also, Islam raises the bar in terms of the source of the message in the first place -- whereas we claim the Qur'an is the direct word of Allah, Christian scripture is not and they don't claim it to be.