39- Quran contains many good teachings. out of more than 6000 verses you pick only those that suit your agenda. 

Your unwavering faith (Faith is always blind. It is belief without evidence) surprise me. You ask me to look at the good things that Muhammad said and not at his shortcomings and mistakes. Let me remind you that Muhammad claimed to be a messenger of God. He is supposed to be the guidance to humanity. If it is up to us to sieve between the good and bad and use our own judgment to choose, why we need him? 

Also everyone has good and bad points. Even the worst criminals have said and done something good in their lives. For example Hitler was not a womanizer. He was a faithful man. Does that make him a good person? I recall when I was a kid in Iran they used to interview the criminals in jail and transmit it in the radio. At the end always these criminals had good advises for the youngsters. Muhammad said many good things but he did not follow his own advice and did very bad things. Your logic that we should look only the few good things the Muhammad said or did and forget about his crimes against humanity coming from an educated man is mind-boggling. 

Someone who claims to be a divine guidance to humanity and infallible must be infallible and a guidance to humanity all the time. If you have someone who sometimes tell you the right thing and other times tells you the wrong thing, would you still trust him? Who is to determine what part of Muhammad’s teachings are to be followed and what part are to be discarded? You have a different value system than Mullah Omar the leader of Taliban. Each one of you chooses what he pleases from the Quran according to his preferences and values. Can you still say this book is a book of guidance? 

If there is one single error in anyone’s teaching who claims to be an infallible guide from God that person is no more an infallible guide. In the case of Muhammad there are more bad teachings than good. How can any intelligent person consider such a man as a messenger of God?