So here's what the argument back will be...
"Your honor, my client was not protesting anything or intentionally obstructing traffic. Poor Johnny Smith was trying to get home after his volunteer hours at the church/doing his homework at the library/helping elderly ladies home from the grocery store when Mr. Driver negligently ran him down with his Ford Truck that allegedly had a Confederate flag on the bumper and what appeared to be a white hood in the back seat. For those reasons, this matter should proceed to trial."
On a serious note, what the issue will end up coming down to is whether the determination of protest/impeding traffic will be an issue of law (judge to decide) or an issue of fact (jury to decide). If they make it a factual issue, then the suits will still be filed, and the drivers will be forced to defend.
(As an aside, the way the statute is written, it appears that it will be a factual determination.)