I used to live next to a popular bike trail, that had 0 sharing with cars. Not a road within 50 meters. There were plenty of injuries. Bike vs bike, bike vs pedestrian, bike vs stationary object, distracted cyclist injures themselves. Etc. If you're going 30 km/hr in thin lycra, you can certainly injure yourself with no help from anyone or anything else.
If you put on special dress for an activity, don't skip the helmet. Same as driving, actually: people who don special driving kit wear a helmet with that, everybody else drives without.
When I spent time in a French hospital after bike helmet use (not involving a car by the way, except for the ambulance that called the helicopter), I was really curious if I would continue that pattern or become of of those "helmet even on civilian clothes rides" people. Was expecting the latter, but nope, would still feel as alien as putting on a helmet to drive.
There are many people who cycle for transportation. In order to utilize cycling for transportation, people need to maintain higher speeds, or spend a lot more time commuting each way. Just dismissing their needs by calling them sports cyclists because they ride at faster speeds doesn't do anyone any favors.
Not sure exactly what your point is. The risky behavior being referred to in the article is partly going faster than one should. You're basically making the same point, in order to go faster you feel you must wear a helmet, which if you flip around, you don't go as fast when not wearing a helmet. Not going as fast is less risky behavior.
Now you can decide you want to bike faster, and by all means (and I would make this choice as well), when riding aggressively in any context, you should wear a helmet.
The problem is that pedestrians treat those trails like sidewalks and cyclists treat it like a road.
Mutual yielding (where two pedestrians approach each other on a sidewalk) works perfectly fine at walking speed. It doesn't work at vehicular speeds, which is why the rules of the road exist that determine positioning and right of way. In order to travel at faster speeds, one must follow a set of rules. Relying on mutual yielding results in the collisions you mention.
