Article said he was going 65 when rear-ended by minivan going 70mph. With full-gear, getting tossed onto road at 65mph is easily survivable. What's major unknown is how you'll survive the following traffic. Cars following you & minivan is unknown. Get hit by car @70mph while you're on ground or trying to get up is pretty much fatal.
Seems odd that the rider said he felt the driver of the van "hunted him down". Even crazy people don't do that out of the blue. There is certainly more to the story like perhaps the rider antagonized him or road raged him to invoke. Will be interesting to see the outcome on this one.
I use to moto commute the 91 daily as a youth and it is rough. Specifically there is a Bermuda Triangle of sorts in the spot right between Corona and Green River Road by the 71 interchange. I was almost been killed a couple times (miraculous saves) and witnessed countless insane accidents there going both directions. I don't know what it is about this spot but please exhibit extra caution if you ever have to go through there.
EDIT: uploaded pic of left ring finger as a constant reminder of the 91 freeway. That tip of my finger got snapped by my clutch lever all the way back to the bar when a guy in a 240z wheeled me! :wow. Very serious when I say please be careful out there.