Then they surrendered, and the apostle confined them in Medina. . . . Then the apostle went out to the market of Medina (which is still its market today) and dug trenches in it. Then he sent for them and struck off their heads in those trenches as they were brought out to him in batches. . . . There were 600 or 700 in all, though some put the figure as high as 800 or 900. Every male who had reached puberty was killed. Muhammad divided the women, children, and property among his men (taking a fifth of the spoils for himself).You wonder why Christians and secular society does not make these facts known. We believe in truth don't we? We don't want people making big life decisions like becoming a Muslim without knowing the relevant facts. So why don't we do our best to make sure these things are known? The short answer is we are cowards. We have gotten very good in the west at steering clear of those pesky doctrinal issues that can lead to arguments. So we have developed an etiquette around religion that you don't want to be negative about what someone else believes. There was a real problem. Many people were getting into very heated arguments and even wars over fairly minor doctrinal questions. There was a time in the west when all the major religions were Christian and all Christian groups were much more orthodox in terms of doctrine and morals. So it hardly seemed worth the trouble to risk hurt feelings over such matters.
There are many things wrong with such thinking but one problem is knowing where to draw the line. When does a problem with a world and life view become serious enough to point out? Once you accept little lies they tend to grow into big lies. You just start processing things different. Speaking the truth in love is no longer the focus. Avoiding conflict becomes the game. But you don't end up avoiding all fights. You just end up fighting over lesser things.
What strikes me about Muhammad is that he had this virtue of courage that our society is lacking. He believed some wrong things but he never backed down from them. It was not easy. People responded to someone who believed what he believed so strongly he was able to accept personal risk and sacrifice. That kind of moral courage impresses people, especially young men. Even today we wonder why young men are attracted to Islam. Sure they lack self control but at least they have some passion that needs controlling. Dead people have excellent self control but nobody wants to be dead. People who avoid talking about religion except in church are spiritually dead. Why would anyone be attracted by that?
So Islam is a threat as well as a hint. Give people something to believe in and they will respond. We could even have the courage to put Muhammad and Jesus side by side. Which is greater, the courage to kill or the courage to die? Muhammad fought for what he believed was good but he used the weapons of Satan. Jesus fought with total self-sacrificing love. Something Muhammad was unable to accept. Jesus always respected each person's right to choose for Him or against Him. Muhammad? No so much. Why don't you hear sermons like that? Because we might offend someone? That fear is far more offensive than a charitably presented truth could ever be.