A trauma surgeon is well entitled to pass comment about injury.
He is not qualified to comment upon the external physics behind it, any more than Einsteinm a renowned physicist, could give a credible insight into trauma surgery.
For example, I doubt he could accurately tell you the rate of acceleration of an object under gravity without checking. If he's well read he might get close and say 10m/s2, which is still far enough out to produce significant error when calculating the fall of an object - such as a cyclist - due to gravity.
For example, if he knew about acceleration due to gravity he would know that a heavy ebike falls at exactly the same rate as a super light carbon job.
As such the weight, more more correctly the mass, of a bike is irrelevant unless it actually lands on your head, in which case helmets are a moot point as they're not designed to provide protection in vehicular collisions, only contact with the ground.
Such matters are simply beyond his expertise, yet he feels qualified to comment upon them with authority. This must surely be seen by any reasonable observer as odd.
He is stepping beyond his own training and expertise and is stacking assumption upon preconception and demanding action on the basis of the resulting faulty reasoning. When politicians do this we call it populism.
There may well be something in that which he claims, but the arguments he presents are faulty.
The matter needs proper, holistic investigation by those qualified in every field involved, and not simply the voice of one person who is stretching credulity beyond the limits of his actual expertise. Indeed, the keen amateurs above have already picked fault with some of his reasoning and assumptions, or at the very least raised credible doubt worthy of proper research before anyone gets remotely close to basing legislation upon it.
As aforementioned, we have politicians to talk pants for us. We do not need supposedly learned people joining in such behaviour.
