Problems with cars should be addressed by restrictions on cars and car operators. There is no reason not to do this. Although we can be stupid about it, that's not a reason not to do it - rather that's a reason not to be stupid about it.
In the US at least, cars are and continue to be a way bigger problem, and the thing is nobody seems to be putting any effort into that. One concern is that the availability and usefulness of ebikes is currently offering an alternative to cars that is massively safer for other people. Injuries on bikes and escooters are much more likely to be the rider than injuries in a car accident are to be the driver.
If we focus too much on the much smaller danger of ebikes, then we push people back to cars, and actually cause more harm. This means that there simultaneously has to be increased regulation and standards for cars, if there is going to be regulation that decreases the usefulness of alternatives, or legislation to increase public transport at the very least.
While I think overall it would be good to flesh out regulation, I think it would be quite bad to choose to restrict ebikes as we try and shift away from car dependency. If you directly compare numbers, ebikes and even escooters are quite safe per mile traveled.
I consider myself a reasonably good driver, but I also tend to drive a little fast and a little aggressive. So instead, I bike. If I do something reckless while I'm biking, and I splat against a car, it's unfortunate for me but just a bad memory for everyone else. Much preferred to a car.
This is also why I think some age limits and restrictions would be good. I choose to do something potentially more risky for me because it's less risky for others, and I'm an adult. That choice gets more iffy if it's a child making it, hence maybe class 1 ebikes only for <16yo.
This problem takes a different form in many other countries, and I'm not that familiar with transport in Australia.
tl;dr regulating ebikes without consideration probably results in more consequences for innocent bystanders, and deaths from cars need to be managed a lot more before we need to consider tightening current ebike classifications. Deaths due to transportation would overall go down if ebikes and moped classes were more available and applicable, IMO.