There's video of them throwing Molotov cocktails.They clearly brought them with them whether the tear gas or the cocktails flew first. There clearly is justification for peaceful protests, but there seem to be elements among the protesters that want to escalate the situation into riot. Many credit MLK's peaceful marches with the great advances in civil rights in the 60's, but I don't think they would have been as effective if there hadn't been violent riots occurring at the same time that forced the powers that be to pay attention to the situation. Sometimes you need to smack people with a 2x4 to get them to pay attention.