Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

Can you not see that safety equipment can be used in conjunction with riding as safely as possible?

If wearing a helmet made it impossible to ride safely then I would tell everyone 'don't wear a helmet under any circumstances'. But it doesn't work like that, one can wear a helmet and ride safely.

One problem is that people tend to unconsciously normalise their behaviour to achieve an acceptable level of risk. This unfortunately negates any benefit of safety equipment. In other words, if you wear a helmet you ride more dangerously even if you have no intention of doing so. This of course increases the probability of other injuries that a helmet does nothing to protect against.

The problem with the rock-climbing analogy is that in climbing you are dealing with an inherently risky, natural environment. Rocks get wet or dusty and they can break, making falls likely or untimately inevitable. For simply riding a bike on the road at commuting speed the risk of a fall is hugely lower. The real risk is from motor vehicles, which many people insist on seeing these as a similarly inherent, natural risk. Of course they're nothing of the kind, they're only there because we allow them to be and every one is controlled by a person. The insistence on safety gear is therefore misplaced since we can (and should) deal with the source of the risk (i.e., motor vehicles and crappy driving) rather than trying to reduce its impact through safety gear.