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
Similar role, suicides are like 10x higher than motorcycle deaths. I assume overdoses are similarly high because the US is grim so you'd expect a higher rate of grim deaths.
I haven't looked at the data but it's a safe bet that motorcycle riders are most likely to die from cardiovascular causes.