Critical thinking can tell you there is a higher chance the women were sex trafficked considering the employer and his immoral proclivities. It can't tell you if they actually were or not.
1) If a powerful man who has been accused of sex trafficking
2) shows up with two girls less than half his age,
3) who are from eastern europe (while he is an American, not exactly where he'd get girlfriends or assistants),
4) he passes them of like his "assistants",
5) while they look like models,
6) and they make everybody uncomfortable to the point of telling them to signal whether they're there against their will
then critical thinking says he's more probably than not indeed sex trafficking, and there's something really shady in his relationship with the two girls...
Not, "they're surely just his assistants, nothing to see here, why would anybody consider anything else going on without some written testimony, a full confession and perhaps lab evidence?"
Each and every one of those people underneath Ito who suspected something might be up had the opportunity to do something about it, including going to the board, and given their suspicions they should have. And yet, nobody did.