It's the government's way of keeping people out of the country. Giving someone your password is a violation of Facebook's TOS. The DOJ says violating the TOS is a felony under the CFAA. So if you give them your password, you've committed a felony, which is grounds for refusing you entry to the country.
"...Comcast will suffer significant, irreparable injury to its property, operations, and customer relationships."
For once Comcast might be telling the truth. After all, if Comcast is forced to compete there will ge irrepairable damage to the profit margins, Comcast would also be completely unable to maintain the current levels of customer service.
As with any totalitarian government and government wannabes, (I'm looking at you Mafiaa!) the entire goal is controlling everything. Guilt, innocence, truth, lies are all irrelevant to them. Open software cannot be controlled, so it must be stamped out, by any means necessary.
The DOJ will take all this information and bury it in an archaic file system. It will be strangely unable to find any of this collected information, except when it's useful to the DOJ to have the information public.