If these fellas want to show their commitment to changing it will require two things in my opinion:
1. A prolonged period of time without further incident.
2. Perhaps some dedicated effort to supporting, monetarily or otherwise, the elimination of this sort of behavior at the structural level? Start a campaign against sexism/harassment or something? Though to make it not appear disingenuous they ought to do so in a fake name--that's the problem when you're outed as a manipulator in a position of power, literally every subsequent move you make reads like manipulation. The McClure case as described in the NYT article wasn't too extreme and it is possible that some of it was misunderstanding and the he is being honest--it sounds like, for instance, 500 could have decided to end their conversations with Kunst for reasons beyond the message, but we'll never know. For instance I cannot help but feel the majority of this piece is McClure looking out for McClure and not giving a shit about actually being sorry. Of course I don't know that, but trust is difficult to regain.
Granted, McClure's fuck up does jive with the context he describes here, but it just becomes very difficult to believe any of these apology letters are genuine until some time has passed in which that is shown to be the case.