I can personally speak to there being certain clauses within contracts that prohibit people from speaking about certain things. As an assistant coach, when I finally did get a contract with the association, there were certain clauses, things like non-disclosure agreements, whereby you couldn't talk about a situation. These are tactics that are used to silence people coming forward, or, when they have spoken, to punish them.
There is also the complicity...or the whole culture of permissiveness that is fear-based. People will not come forward if there is that threat of reprisal. That is an ongoing, cultural, systemic issue. People stay very quiet and aren't willing to risk coming forward to be a whistle-blower.