The original in "WirtschaftsWoche" does not use such a strong wording in my opinion. I am Spanish native but work using German most of the time in central Europe.
In my personal opinion traveling around the world I find the Muslim countries in lots of ways having opposite principles to Western values.
They are not compatible: Mohamed told them that adultery women had to be punished with stoning death, Jesus response was forgiveness.
In Qur'an it is said that anyone that does not believe in Ala, Christians and Jews should be killed, including those that call their selves "Muslims", but are not real Muslims. Of course Mohamed could say who was real Muslim and who was not. In other words he could kill anyone he wished with no consequences.
Jesus told everybody should be respected, including those that believe in something different, or did not believe at all. A great difference.
Mohamed married a 5 year old girl and consummated the act when the girl was 10, so by Western standards he was a pederast.
If you believe that Mohamed is God's prophet you have to believe all he did is ok if you do yourself.
Muslim countries are not open, I have visited countries were they kill you if you define yourself atheist or homosexual. There are atheists there, they will tell you as foreigner, but they could not tell anybody in their own country.
If Europe opens the gates to Muslims, Europe will became a Muslim territory. As a European I don't want this for Europe.