I wouldn't say they're "deregulated" in the US. There are still a number of rules that pilots have to comply with (for instance, no commercial use, limited fuel capacity, limited areas where flight is allowed, etc). Sure, a license is not required, but the US will find a way to complicate things with red tape even if a license isn't required.

"Limited areas where flight is allowed" is actually very permissive; in class G airspace you could go anywhere. If you take a VHF radio and ADS-B out transponder with you and have done the radio exam from the PPL, in theory you could call up the Tower at a class B/C/D Airport and ask to land. At deltas they might actually let you.

Watching some videos of people flying these things on YouTube, it's almost like they want the aviation agencies to crack down on them.

I've seen; low level acrobatics, low flight over people, guys taking off with no training and no instruction.

Reckless airmanship leads to deaths, but the paramotorists often blame it on the equipment, because without any agency investigating, there is only speculation.

There is an electric paramotor, with four drone like blades. That thing looks awesome; instead of the sounds and vibration of a 2-stroke engine strapped to your back, it's silent when you let off the throttle to glide. And no worries about will that lawnmower start up again.

For some people there are more important things than a small risk of death. I suspect these risk-takers make up a disproportionate number of paramotorists

Well air law could be argued to prohibit doing that, as it just states that you shouldn't do anything dangerous (at least EU), Id argue flying without the proper knowledge definitely falls under that. However air law can be argued onto anything, i.e. in Germany you aren't legally allowed to throw a paper airplane without special insurance, which is generally not covered by most insurances.

I saw this guy flying one of these beyond the trash fence out at black rock. Just skimming along the ground then heading back up into the air. Looked like a lot of fun.

I read 'perambulators' and was very confused for a while.