"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
So do hedonism, political correctness, cowardice, moral relativism, and abdication of responsibility in a nation's leadership.
It all carries consequences, and it all adds up over time, and all the chickens eventually come home to roost. And the fallout and misery don't come until the problem is too big to fix.