Slowing down in a mob infested area doesn’t generally work out well for the driver (or the vehicle)
True, but reports are that the stretch of I-5 was closed by the cops well before the incident. From the link:
Officials were trying to determine the motive as well as where he got onto the interstate, which had been closed by the state patrol for more than an hour before the protesters were hit. Mead said they suspect Kelete drove the wrong way on a ramp. Trooper Rick Johnson said the driver went through a barrier that closed the freeway.
So much for the driver being an innocent victim.