Absolutely Agree! I also believe that most of the media-released statements from "witnesses" came within the first week of the disappearances, when the girl's were only classified as "missing" and when there was a massive search for them. Once it became apparent that the disappearances were more than just "missing", the witnesses no longer spoke publicly, and LE released less information.
I also don't think the media-released statements were initiated by the witnesses and some of the family members, even though they did speak publicly. In other words, they didn't call a press conference to announce to the world what they saw! Media networks will hunt down anything and anyone pertaining to a high-profile or newsworthy case to "get the story", no matter what. They will fly a helicopter above your house and property, park a news van in front of your child's ball-games, camp out in your driveway, call your house and employment non-stop, contact anyone in the community with the same last name, and broadcast your 9-1-1 calls all over the country until you give them the story or seek the assistance from LE for privacy! This was done to my relative without the name being made public (thanks to a "gag" order by LE)!
If you no longer talk publicly, because your story is irrelevant, you can't tolerate the media and public stalking, or you've been advised by LE to keep quiet, then you are made out to be somehow involved with the crime, or everything about you is aired publicly and scrutinized (IMO what has been done to witnesses and some family members in the girl's case).