I decided long ago that if I would hold no other idea, freedom or philosophy above all others it would be this...that while I may wholy disagree with what you have to say, I will defend 'till my death your right to say it.
Academically, I am a journalist (having spent 4.5 years studying journalism in college) and I have a decent grasp on the legal and constitiutional basis of our freedom of speech. I have also researched this group rather thoroughly (I was in charge of tasking my Brigade with it's funerals).
These people are very smart. It is my understanding that large percentage of them are lawyers. They videotape everything and know the laws of each city, county and state that they protest in. They purposely provoke folks right up to the legal line and when someone else, out of anger, steps over that line and pushes them, hits them or some other pysical contact, they sue the individual for "assault", the police department for the lack of protection and everyone else that they can. In a court of law, they are found to be the victims and win massive lawsuits. Thats how they fund the activities, travels, etc.
Just like martial artists have techniques dealing with specific threats, there are techniques to render these amoral attackers harmless without breaking the law.
1. Although the constitiution states that "Congress shall pass no laws restricting the freedom of speech and to peacably assemble" (paraphrased for brevity), each locale has the ablity to legislate the Time, Place and Manner in which a demonstration can take place. Petition your local government (state, city, etc) to enact laws that restrict the TP&M of protests in your area (i.e. No protestors permitted within 500meters of any funeral or memorial service from 3 hours before to 3 hours after the event). Several states have already done this. Make these folks impotent.
2. If you find out that there is a planned protest in your area (they keep a schedule on their website), contact all the local media and beseech them to NOT cover the event or to give it minimum coverage. The more coverage they get, the more they get their message out. Render these folks more impotent.
3. Also, organize counter protests. Use their right against them. Anytime there has been a counter-protest to their drivel, they have been phenomenal turnout to counter them (massively outnumbered). If there is media coverage, it will be for the counter protest and it will put the original protesters in a negative light, showing what type of folks they are.
As a soldier who has lost friends in this war, it boils my blood to listen to their retoric. Render them ineffective and you will have defended those who have lost their lives defending you.