In New York cyclists are supposed to stay to designated cycle paths unless there is no alternative. In most other parts of the USA there is not special cycle path so cyclists are allowed to "take the lane" and hog up one car lane.
We don't know exactly what Casey Neistat was doing when he got a ticket for not riding in the bike path but he felt it was unjust. He went on to create this well crafted video of why the law should be "flexible" and how dangerous the bike paths really are in New York City. It probably safer to "take the lane" if it was allowed.
My take on this video is that New York City is no Amsterdam. They've tried to make safe cycling paths but there is not a clear mindset of the general public of what they are to be used for. As long as cycle paths are not safe this law should be abolished.