Thanks for getting in touch and I apologize for the delayed response—this post seemed to slip through the cracks.
To clear up any confusion, the 70mph threshold isn't meant to be a behavioral change or a reflection on the speed limit in your area. Rather, multiple studies have proven that driving over 70mph for an extended period of time results in lower fuel economy.
You can find more information regarding this decision in the Official Response from our Head of Product at this post.
As you will find in that post, the scoring isn't meant to penalize you as a driver since the score isn't meant to reflect on how good of a driver one is. Score simply measures your vehicle's fuel efficiency.
I too have to chip in. You state that deducting points for going over 70 mph isn't geared toward penalizing us for our driving behavior. However, it deducts from the score. You may choose to call it something else, but that's the very definition of a penalty. I went from 99% to 58% on the last driving day of my week for cruising between 70-75 mph for 20 minutes. I never went over 75. Over the whole week, I was motivated to having softer accelerations/decelerations to improve fuel economy and driving score. Now I see that it makes no difference. Either I'm the slow guy going 69 mph in a 75 mph zone or I have a bad score. Automatic is being sent back. You can decide if you want to fail at business or allow people to choose their threshold. This is too ""progressive"" and illogical.