That’s because for a period of time they were poorly manufactured and quite literally exploded. Since there were no real brands as they were imported before the

That’s because for a period of time they were poorly manufactured and quite literally exploded. Since there were no real brands as they were imported before they became mainstream they just blanket banned them all. There have been other devices banned for similar reasons, like the Samsung Galaxy Note7: https://www.transportation.gov/briefing-room/dot-bans-all-samsung-galaxy-note7-phones-airplanes https://www.transportation.gov/briefing-room/dot-bans-all-sa...