Earlier quoted context omitted.
because investigations performed by the companies or governments themselves tend to portray themselves as not culpable for any actions (often omitting pertinent details). Independent review is the only way to be honest.
These reviews are not necessarily independent. If they don't yield any results the organisations lose their funding. So they have the incentive to be as dishonest as Apple and China are.
Do you have any serious evidence? Otherwise we are raising random possible problems. Maybe it's a false flag! Maybe it's the CIA or FSB or Martians! Maybe! Not necessarily!