I find it hard to believe anyone here is against bicycle helmets.
I can only see people who think helmets should not be mandatory, because the data shows this will reduce the number of people using their bicycles for casual transport, which in turn increases their risk for a wide range of health problems and simultaneously makes cycling more dangerous for everyone else, because fewer cyclists on the road means fewer drivers will take enough care to notice them and give them their space.
However, it pays substantially less for such folks as it does for the folks such folks are angry about.
Bicycle related injuries are not what any insurance company is worried about, while obesity, diabetes, cardiovascular diseases and motor vehicle related injuries actually really are the issues that keep raising the cost of your insurance - you just don't see it that way, because you don't want to take responsibility for the costs your lifestyle imposes on the society.
I'm dreadfully sorry if this has come out as addressed to an individual - speaking epidemiologically, this is absolutely about all of us, collectively. I would never recommend anyone to not wear a helmet, but I would rather see their choice of transport be the bicycle as often as possible, and mandatory wearing of helmet will not help that.
I've been commuting by bike ( http://www.youtube.com/watch?v=TgvjnOJwWTU ) for about 20 years now and I feel that every motor vehicle occupant should be wearing a helmet.
The case is quite clear: Most people who die in cars have not had their heads protected by a helmet at the time of the fatal collision. While they might very well be dead regardless, so might the occasional cyclist that got run over by a lorry while not wearing her helmet, so this doesn't really enter the argument.
When helmets are mandatory for car occupants, I shall laugh at their faces and ask them if they feel any safer crossing the railroad tracks. I'm also certain my ill manners will improve road safety by a measurable margin.
I can only see people who think helmets should not be mandatory, because the data shows this will reduce the number of people using their bicycles for casual transport, which in turn increases their risk for a wide range of health problems and simultaneously makes cycling more dangerous for everyone else, because fewer cyclists on the road means fewer drivers will take enough care to notice them and give them their space.