Not sure how many bothered to read the actual report.
They were able test pills from the actual prescription to confirm that the her prescription medicine was tainted. The levels that appeared in the pills were found to be consistent with the levels found in her sample.
Simple google search turns up countless articles of this particular substance showing up in all kinds of medication. Off the top of my head, I remember seeing numerous cases of it contaminating Valsartan, which is one of a handful of the most popular blood pressure medications worldwide.
This certainly wasn't a case of an athlete playing dumb to try and get away with something. Nor was it a passive violation where the athlete neglected the "I'm solely responsible for what I put in my body" code. It's not like she was buying sketchy vitamins manufactured in a basement by a handful of clowns for couldn't complete their AAs whose products only list "proprietary blend" as their ingredients either.
Cut and dry cases aren't the norm so I guess I understand some initial skepticism, but summoning the energy to click a link and do a few paragraphs of reading would tell one all they need to know.