I haven't read the article yet, but I would assume the starting point is this: a large, large percentage of pre-dynamic kickoffs were touchbacks into/through the end zone with almost zero concussions.
The league got what it wanted - more returns. But with more returns come more collisions. Probably fewer grisly knockout type concussions, but more than with a kick through the end zone.
After watching this for a while now, I think I'd like to just have the receiving team have the option of getting the ball at the 35 or having the kicking team kickoff with the new rules. Unless a team is trailing late it's likely to just take the 35, meaning zero injuries. But if you are trailing late, you get the option of trying for the big return.