it’s about cars turning onto side streets and it happens at a lot more than 5 MPH.
I have mirrors, so I check behind me for cars turning right and I can see oncoming traffic for cars turning left.
You have to factor the probability into the risk, not just the severity
My primary concern is the severity. I feel way less safe riding in the street. All it takes is a semi-truck swerving a few feet, a drunk driver not paying attention, or someone looking at their phone at the wrong moment and it's game over for me. The stretch of my commute that I have to share the road with cars is the worst part and if I had to do that the whole way I simply wouldn't cycle anymore.
The real problem is a lack of bike infrastructure, but until that is resolved I'm going to ride where I feel safe and that is as far away from cars as possible. And I'm not on an ebike, just a regular one. I only go 10-15 mph.