Human powered bikes at 20mph give you an accurate sense of the power behind your velocity because you are personally delivering that power. That also isn't the average human cruising speed, that is speed achieved by experienced riders. Riders with enough experience to control the bike in all kinds of wonky scenarios.
But an e-bike can make high speeds feel like a casual stroll, and get someone to that speed when they do not have the experience to control it. I love fast bikes, but I also am acutely (perhaps overly) aware of the safety implications of them, as I have taken a tumble off a bike at high speed. Broken bones, road rash, hospital stays, PT, and years of chronic pain as a result. I still love me fast e-bike, and still ride it (carefully), but I am under no illusion that it isn't fast.
I agree with the overall point that e-bikes can hit higher speeds more easily. But those speeds on normal bikes aren't the sole domain of experienced riders. Going down a two or three percent grade at 20 or 25 mph is something that a normal bike rider experiences all the time and needs to learn to be comfortable with.
But an e-bike can make high speeds feel like a casual stroll, and get someone to that speed when they do not have the experience to control it. I love fast bikes, but I also am acutely (perhaps overly) aware of the safety implications of them, as I have taken a tumble off a bike at high speed. Broken bones, road rash, hospital stays, PT, and years of chronic pain as a result. I still love me fast e-bike, and still ride it (carefully), but I am under no illusion that it isn't fast.