Why some religions (appear to) promote violence?

In many of the cases you quoted, it is the religious leaders that control both the politics and the media. Many, not all, leaders have their own agenda. The Bible was crafted in the third century and many books were omitted from consideration. The Koran was written by a man during many mood swings and subject to his views at the moment. Much of the Torah was borrowed from other sources found in the Great Library created by Gilgamesh. Several sects of Buddhism took only sections of the Lotus Sutra while others are based on early teachings when there were over 200 commandments for men and more that 500 for women. So you would need to study all religious writings to piece together what the intent really was. The same can be found in listening to Fox, CNN and the BBC. The truth is often between the lines but still open to subjective interpretation.