Whenever I see blanket statements like this in such studies ~ it's like they're trying to avoid pissing any powerful corporations that profit from whatever we're told to not draw any conclusions about. They don't want to potentially endanger their careers.

Drug companies hate it when a cash-cow drug is threatened in any way. Anything that threatens those profits is a potential target in one way or another. Researchers studying these drugs know just how much power and influence these drug companies have, and so, are afraid of angering them.

The reasoning is simple ~ make a vaguely disqualifying statement that hopefully keeps them in the good books.