Wikileaks & Snowden already talked about this. Playpen was being run by FBI for quite some time. *They shut it down when they were exposed as running it. *

This absolutely not true. The case has been going on since 2015 and Playpen has been shutdown since 2015. The got a court order to operate it for two weeks to trace and track down the other criminals involved. The "exposure" came when the revealed to the lawyers of the people arrested why and how they were arrested in the filings before the court.

Here's the court documents filed back in 2015 in one of the first cases that went to trial

https://pbs.twimg.com/media/CJ5VrzsUMAA_PrZ.png

One person arrested challenged his arrest in court and lost, this is from January 2016 and clearly says the FBI ran the website for two weeks under a warrant. http://www.reuters.com/article/us-usa-crime-childporn-idUSKCN0V72D5

A Washington state school administrator has lost a high-profile bid to suppress evidence against him secured by the FBI during an operation in which it secretly ran one of the Internet's largest child pornography websites in order to catch its users.

U.S. District Judge Robert Bryan in Tacoma, Washington, on Thursday rejected arguments by Jay Michaud, one of 137 people facing U.S. charges in the probe, that a search warrant that enabled the FBI to conduct the sting was unconstitutional.

In order to identify its 214,898 members, authorities sought a search warrant from a Virginia judge allowing them to deploy a "network investigative technique" that would cause a computer to send them data any time a user logged on while the FBI operated the website for two weeks.