I feel like you’re missing that the brakes on current (decent/non-shit) bikes are quite satisfactory. And that cyclists normally dont ride at 28mph, unless going downhill. And that regardless of vehicle, it is up to the rider to be safe for the conditions.
Yes, locking up your wheels is bad. The same is true on a car. It is good that on small mechanical systems with feedback, it is easy to not lock up the tires.
On top of that, many ebikes have regenerative breaking, which makes it easy to maintain a good speed.