The Supreme Court already ruled on Westboro, they can still protest outside a buffer zone between them and the funeral legally. I believe La. has such a law that implements a buffer zone, and if it's violated the demonstrators are subject to arrest.
its always tricky to word this statutes in such a way that courts see them as tolerant of the essential right to protest or express themselves, yet still achieve a legitimate government aim of maintaining civil order, and the rights of others.
Really folks, how loud do you want your neighbors to blare their stereos on their property at 3 am without a cop telling them to turn it down? Do you really care that the lyrics include social or political commentary?