The rise of junk science is a result of the increasing amount of scientific evidence admitted in civil courts. Expert witnesses are called by both sides to introduce and explain scientific evidence. Often experts expose opposite conclusions. None of these are valid scientific theory. The 1993 Supreme Court landmark decision Daubert vs. Merrell Dow Pharmaceuticals has become the standard for admissibility of scientific evidence in federal courts and many state courts.
Scientific validity is now the litmus test for admissibility of scientific evidence.