Not just you, they're all over the place here. Kids on choppers and various other stripped down bikes with no lighting at all has been happening for years. Looks like they're all getting jobs now.
Old fart on an e-bike with forks like a Harley appeared in my rear-view mirror today. Traffic slowed at a roundabout, so he undertakes me, sorry filters past, meaning that I now have to allow him 1.5 metres or else travel at his peddling speed of 10 mph. The difference is that as soon as an opportunity to pass him (with a suitable clearance) arises, his motor cuts in and his speed goes up to around 25 mph, so I can't. He did exactly the same twice more before my turn-off. I wouldn't be surprised if he's a car driver as well and probably drives a car every bit as selfishly as he rides his bike. I also bet that he isn't as concerned about other cyclists' safety as I was.
Edit: just checked and I see that the power-assist must turn off at 15.5 mph by law in the UK. All I can say is that this "cyclist" must have acquired his motor from "some other" source.
EDITED: 22 Oct 2023 17:09 by WILLIAMA