The role of journalism in a report like this isn't to effect the arrest
or apprehension of those breaking the law. It is to expose the law
breaking.
Journalists enjoy a privilege called "confidentiality of sources" and
are not required to identify the people in the report. That's why their
images are blurred.
Of course Dateline's "To catch a predator" had no problem following through. Many "news" stories have been staged, and later revealed. That this one hasn't doesn't mean it's real.