They ignore it as long as there is a vocal contingent of people against cycling infrastructure because of cost or because it may create a slight disruption to a car.
Some do, sure. But thankfully at least where I live governments (both state and local-level) have seen the benefits of improving cycling infrastructure and are continuing to do so. A good many car drivers are quite happy to not have to share roads with bikes too! Well-built cycling infrastructure makes roads better for all users, esp. if it can reduce the number of unnecessary car trips.