Not to justify things, but this was in front of everyone's eyes for 5 years. Therefore I assume:
a) nobody looked at it,
b) some looked at it and didn't bother to further investigate,
c) some looked at it, investigated, and the findings were quietly buried. I.e., it was known but inconvenient to act on,
d) some saw it, investigated, understood the severity, but lacked the authority or leverage to force action.
