Giving aid and comfort to the enemy is not a violation of the law?
I would describe this conduct as that of a preacher of hate who sides with the enemies of this country. How is this guy different from the radical cleric recently convicted in the UK who also supported ISIL? If the FBI thinks they need a new law to deal with the preachers of hate, they should tell Congress. I am sure they would find support for such a law in the GOP-led Congress.