"MSF courses tell you to use both brakes equally, and rear-only is completely wrong."
Not exactly. The MSF recommends using both brakes to stop so you will develop the habit of using both when something happens that requires maximum braking. If you apply both brakes properly, you will stop in the shortest distance. Can you use only one? Sure, after all who's riding the bike? You're the one who makes the final decision. What are the road and traffic conditions? What kind of bike are you riding? These and many other factors will come into play when you decide what to do.
Not exactly. The MSF recommends using both brakes to stop so you will develop the habit of using both when something happens that requires maximum braking. If you apply both brakes properly, you will stop in the shortest distance. Can you use only one? Sure, after all who's riding the bike? You're the one who makes the final decision. What are the road and traffic conditions? What kind of bike are you riding? These and many other factors will come into play when you decide what to do.