My anecdote only but the contraptions being sold as “e-bikes” are actually motorcycles. Like all things a few bad apples ruin it for everyone but in what I have seen it’s more than just a few bad apples. From maintained mountain bike trails, to riding at speed on walking paths. They are far more than just some kids being kids. It is ultimately a lack of parenting these days but I don’t believe the new laws coming into place are out of line. A vehicle that can hit 30mph within a few seconds is a lot different than a kid peddling at 20mph sustained.
I live in WA (south of seattle) and your description is accurate, there are kids riding around on sidewalks in the area around my house on electric motorcycles that are sold as e-bikes. While I don't personally love it, they kept their distance from my small kids so I figure "let kids be kids". The one instance that frustrated me was they also show up at local mountain bike and skate parks. There they ride up the down trails and destroy a lot of the trail edges, a couple of times I've asked folks to leave.
I was hopeful when I saw the new law that it'll be used as a tool to take action on actual problem usage without punishing those using them safely. Unfortunately I'm aware of the history of laws like this, so I'm worried it'll just be used against lower income / privilege folks. We'll see.
Your description is not accurate for my state, California, there are clear tiers of ebikes with regulations on when and where they can go, with very clear explanation at purchase, and no weird marketing like you're talking about. I've tried to go buy them, I have experienced the lectures!
Perhaps we can let the few bad apples killing lots of people with their massive hood height lead to better regulation of such hood heights?
We have literal deaths on one hand, and on the other, fears that are already heavily covered by regulation. I don't know Washington, but the laws around the speed regulators, etc., for e-bikes are extensive. People still demand "laws" because they overreact and get fearful.
I just wish people would be more fearful of killing others with their cars. It's the biggest cause of death of children, yet there's no action. Yet here we are, discussing ebikes rather than the real causes of child deaths.