When I was a child, a community policeman came to my school and gave the children lessons on traffic laws and how to signal on a bike.  Looks like these types of lessons have not happened for many bike riders.  Very few signal, many just assume they always have the right of way, and ride wherever they want, including the sidewalk next to the bike path.  We need more training for cyclists.  A license won't guarantee training, but it is chaotic right now and attitudes are hardening between each group of road users.