What do I think? I think that this is a marketing campaign for helmet manufacturers.
Nowhere with a helmet law has been able to show any reduction in risk to cyclists, just a reduction in cyclists. Because cycling confers such huge health benefits, regular cyclists live longer and are fitter, healthier and slimmer than the general public, the reduction in their number means that he real effect of helmet laws is massive and negative.
DfT data may show that there have been more cyclists injured in the last ten years, but helmet wearing has gone up in the last ten years. Just like everywhere else where helmet wearing has increased, so has the danger to cyclists.
Check out cyclehelmets.org for a few facts, rather than the marketing bs of the helmet proponents.