Sorry Graham, what you're describing is nonsensical. Think very carefully about the physics involved and try again. I'll let you have another go before I correct it.
Cryptic clue - it's relative.
Coffee time clue - the bulk of cycling head impacts are with stationary objects such as the ground.
This review of several extensive studies debunks that which you have just claimed. 45 out of 177 fatalities is clearly not a majority, so with those figure angular is clearly not the cause of "most" cycling head injury deaths. It's less than a third. Indeed, of that number, while they exhibit injuries consistent with DAI (as they call it), they can not demonstrate how many, if any, of those deaths were actually caused by it.http://www.cyclehelmets.org/1196.html
Indeed, read this review, and then read the research papers to which they refer (really rather dull I'm afraid) and one can see that the results of the research are somewhat at odds with one another, and the reviewer himself disagrees with some of them. Indeed, with my own education into a field involving physics at Masters Level I can myself find fault with the reviewers on contention on several points. In other words, even researchers can not agree with each other, so finding 'evidence' to supporting one argument, or the other, or either, is easy.
So leaving aside that you have misunderstood the research to which you allude, you appear to have cherry picked research to support your own viewpoint, while ignoring contrary evidence. Not exactly objective.