Look I'm as much "fuck cars" as the next guy but riding a motorcycle on a highway is unironically suicidal. I personally know a guy who got in a bad crash on one but miraculously survived; he had a year long recovery period but will have various pain and dysfunction in his body for the rest of his life. I also know some people who did pathology rotations (state medical examiner office, autopsy basically) and the big three categories of bodies coming in were drug overdoses, suicides, and motorcycle crashes.
One of the facebook comments links to a seventh person who died a few days before these on June 18th: https://www.fox13seattle.com/news/motorcyclist-killed-sr-530-crash.amp
Bicycle deaths per mile: ~10 per 100M miles Motorcycle deaths per mile: ~20 per 100M miles
IMO this shows that they're more dangerous, but primarily because you can go a lot further on a motorcycle. Basically 100% of the danger from riding a bicycle comes from cars. In contrast, it's quite practical to kill yourself on a motorcycle without external intervention. So, if you have already chosen a mode of transportation, behavioral choices on a motorcycle offer much more control over where you fall within that mode's risk spectrum. Wearing a helmet and taking a class make way more difference on a motorcycle, and that's borne out by the contributing factors to fatal accidents /u/nat_turner_overdrive has posted elsewhere in the thread. Seems quite possible that the per-mile risk of a motorcycle rider doing everything right is comparable to that of the average bicyclist. Biking in cities is stupid dangerous of course, every cyclist I know has been hit, but that's a problem with cars not an intrinsic thing.