You seem to be attacking a straw man argument along the lines of "Drivers should hit pedestrians whenever possible." The actual question here is whether pedestrians should be limited in their use of roads (e.g. having to use crosswalks), which is not answered by points like "Why is a pedestrian's safety less important than a bit of energy?" and "If I were to run on foot through the streets, tackling anyone who got in my way…".
Obviously cars should not hit pedestrians, but IMO it doesn't make sense to have the slow group getting in the fast group's way all the time. The time and energy needed for me to go 15 miles without a car is much, much greater than the time and energy it takes for me to wait at crosswalks when I'm walking places. You could weigh pedestrians' time and energy twice as heavily as drivers' and you still end up with it being better to have many (not all, but many) roads be primarily car-places.
The UK's roads are an unrestricted free-for-all and the amount of time you spend in your car having to wait for people walking in the road is far short of all of it.
The roads end up mainly for traffic anyway, because people aren't dumb, and they're well aware that most drivers would prefer to kill them than make the effort to press the brake pedal. But there's no need to enshrine this in law and prevent people from crossing where they please when the road is empty, the traffic light and/or slow-moving, or the mass of people large enough.
Obviously cars should not hit pedestrians, but IMO it doesn't make sense to have the slow group getting in the fast group's way all the time. The time and energy needed for me to go 15 miles without a car is much, much greater than the time and energy it takes for me to wait at crosswalks when I'm walking places. You could weigh pedestrians' time and energy twice as heavily as drivers' and you still end up with it being better to have many (not all, but many) roads be primarily car-places.