The arguments against bike licensing/registration/insurance etc. is that the cost to implement and run the scheme is orders of magnitude greater than the purported benefits. Here in the UK, some house/contents insurance includes cycle liability insurance as the number of claims is negligible and it costs the company very little (not so much cycle theft insurance).

The other oft-forgotten aspect of cycling is that in places with social healthcare, the health benefits from cycling will save money, so it can actually save the state money to introduce free cycle liability insurance if it increases the numbers cycling.