Well, I didn't really mean to imply that it's straightforward. But you're right that people can be obnoxious about demanding that others wear helmets--yelling out their car windows at people not wearing them and the like.
No one likes to be bullied or lectured. Human nature is such that people who are pushed have natural tendency to push back. That's pretty universally true, I think. I also think that the decision not to wear a helmet, for many, is at least partially driven by that kind of pushback. I suspect that there are riders who don't wear helmets who very possibly WOULD wear helmets if they weren't constantly being badgered about it. Again, that "pushback" response is basic human nature.
Still, it's worth keeping in mind that just because a particular course of action is loudly advocated by sanctimonious ********, it doesn't necessarily follow that the course of action itself is necessarily wrong. Just something to keep in mind.
One additional note: I was really interested to find that several people noted that their opinions about helmets had changed as a result of what they read on this forum. I had always assumed that what went on here was just non-productive yelling. It still seems to me that that accounts for perhaps two-thirds of the posts, but good to know that there's also some substantive discussion going on.