The point (pardon the pun) is that you are making a choice to wear a helmet. I am being denied a choice not to. You have the choice, I do not. That is what is being objected to.
And the other issue is that cyclists are being forced to share the road with motorists. And then being made to buy & wear helmets (which are extremely unlikely to be of any help) to protect themselves from the actions of the motorists.