Well we disagree. I think there's way more effective things you can do, and this is demonstrated by the netherlands where I live. For an idea to be good it doesn't just have to in theory be net positive, many things can be net positive if you use tax money for them. The problem is we don't have an infinite government or infinite resources or time, so we should pick good measures.

All the cities maintaining a bunch of locations full of helmets for free pickup would just create more waste. You can have a similar effect without any waste by just having a class that teaches children to ride bycicles at school and tells them the benefits of helmets and keeps helmets there for that one class. This memory would be with you for life, and you'd make your own decision.

If helmets were cost prohibitive I'd be with you, I believe in using tax money for that kind of stuff, but price is not the reason people don't use helmets.