I don't think it's an agenda. I think that it is the first thing people think of when they hear of a motorcyclist being killed in a non-helmet law state. Most people equate lack of a helmet with taking an unnecessary risk.

I think that the general public is nervous about hitting and hurting a motorcyclist, and it makes them feel better if they can subconsciously place some of the blame for the severity of the injury on the rider. I'm just speculating, but I think there's some truth to what I say.