It's a conspiracy theory grounded in the very real fact that there are international sex trafficking rings catering to the ultra rich. It isn't unique to the right, however, and conspiratorial thinking is heavily tied to magical thinking and has a lot of overlap with shit like flat earthers anti-vaxxers and new-age crystal healing wine moms. As for real world consequences it has spawned rallies like the ones affiliated with the Save The Children hashtag and early on the man that fired a rifle inside a pizza shop back when it was just pizzagate and hadn't gained much steam. I highly recommend In Search of a Flat Earth by Folding Ideas and The New Age to Qanon Pipeline episode of Qanon Anonymous