You don't see motorcycles in urban parks or on walking paths. They can go 3 or 4 times as fast as the 28 mph limit of a Class 3...
We are going to have millions on ebikes, we're gonna need regs to manage them. People like to think of bicycles (and thus ebikes) as toys. They are transportation, and need to be regulated (and possibly licensed) as such.
Restrictions were fine in the beginning, but as ebikes get more popular, their shortcomings are starting to chafe..