There is no relationship between understanding the Quran and being or not being Muslim
Muslims did not say that the Qur'an is easy to understand
If the Koran was easy to understand there would not be many exegetes
Very good question : If the Makkah verses are useless, why are they in Quran at all? It is to say to those who do not read Arabic: the Qur'an contains only tolerant verses
Most Muslims do not know the violent and Misogynists verses
I take note that you do not show us evidence
All Muslims say the Quran is easy to understand, for Muslims believe Quran to be Divine, and Quran itself says it is easy to understand.
No. Why would I show evidence for what is self-evident? Muslims are creating their own religion, through practice. What Islamic canon says and what people do are not the same thing. Sometimes that works out for good, as in most of Muslims are not doing what ISIS does in aping historical events, and sometimes it works out for bad, like when Muslims force their little daughters to cover.
Muslims are, by and large, not interested in living out the story of Muhammad over and over. They already know that story.
Like you said, most Muslims do not know the violent verses.The reason for this is two-fold, one being that people do find violence pleasant and so do not pick those out for sermons and memorization, and also because people are not encouraged to practice a religion espousing injustice- so imams and madrassahs (until our dear Saudi friends spread their version around in the past few decades) leave those verses out when trying to appeal to their communities.
Doing this creates something maybe other than what was intended by the creators of the faith, and I think that is a good thing. If we, however, could point out the positive results we have obtained by downplaying the negatives and playing up the positives in the religion we could really encourage this filtering. But this is where the Divinity concept holds progress back in Islamic thought and reinforces pesky Islamic Law. This is why I am espousing Hassan's version of Islamic practice.
Christianity gets to use concepts that we do not have in Islam to filter their texts. They have left most of their bad texts behind, save when it pleases them to discriminate or act on their baser instincts. Then they dust off what most other Christians have left behind and they demand men be head of household and women remain chaste and obedient and homosexuals be "rehabilitated". Sometimes when no one pays them any attention they go and kill people to make their points. However it is far worse in other areas of the world than mine. In some places Christians do rival Muslims in murders and mayhem. Any Abrahamic text can be used thus. Maybe even other texts, as well, but I am ignorant of those.