“This is the story of the revelation in late 2013 that Bitcoin was, in fact, the opposite of untraceable—that its blockchain would actually allow researchers, tech companies, and law enforcement to trace and identify users with even more transparency than the existing financial system.”
This is not quite correct. You do not have to involve anybody else in your transaction. What happens is the protocol takes a random selection of 15 other people who have spent money and adds them to a ring so that your transaction could be any one of 16 different outputs. But there is no mixing of funds involved.