I'd expect there to be some efficient optimum somewhere between those extremes.
100% agree
Braking reduces speed, which reduces the energy that's available to do damage to people, which is by definition safer.
I'm glad you brought deceleration and acceleration and energy into the mix. I think I could convince you by framing the discussion with relative energy. I'll use an example I just thought of. Let's say two cars are going 60 mph on the highwayusa represent and one is directly behind the other at a safe* distance.
Two things could cause an accident here. The front driver (A) could perceive a warning and slam on the brakes or the rear driver (B) could speed up and collide into the rear driver. This is a huge oversimplification (normally rear-ends are a result of a combination of the two) but we have to make some assumptions. Let's also assume that driver B is more aware of driver A's actions because it is normal to look forward in fallback-action-situations.
My gut feeling tells me the overwhelming reason for a rear-end accident is caused by one of two things
1) Driver A unpredictably decelerates using the more powerful brakes 2) Driver B fails to react to a A's predictable deceleration
Other reasons like B speeding up to the point where he/she collides with A seems unreasonable and kind of hilarious. But my point is: in the 2 likely scenarios above, driver A's brake use is at least partially a cause for the accident. It may be necessary, it may be unnecessary - but I believe driver A bears at least some of the responsibility for keeping himself/herself and driver B safe.
The problem is that we have laws (here at least) that 100% blame driver B. I believe (I have no factual basis other than my opinion) that these laws encourage dangerous over-conservative driver A behavior. If you cause an accident like in scenario 1, you have no repercussions. See what I'm getting at here? My problem is that all this is 100% my intuition and has no facts behind it other than my own experience.
What I like about the real data you mention is that you can use science on intuition and prove it right or wrong. This science can then be used to make our roads safer and inform driver's education everywhere. This is the good stuff! I didn't even know about this research until we got into a semi-heated but open-minded discussion about my personal opinions and their merits.
Me trying to convince people of things that I believe but have no factual basis for has been a personal problem of mine for a long time. It's hard to keep it in check and I'm doing my best!