My take on why Ben didn't response to Blake

While I know that the main reason attributed to Ben's lack of response is Jennifer, I think there's at least another, more professional reason. Unlike Matt Damon, Ben has 15 credits as a director on IMDB, so I think he can see the problem in Blake's narrative from a director's POV.

The email that Blake sent to him was worse in my opinion than her message to Matt; in Matt's message, she basically vented her frustration and the "uncredited" work she did: rewrote the script and directed every actor etc, giving the impression that JB was totally useless and unable to do his work as director. But in Matt's email, she straight-up confessed to overriding the director and totally lacking any sense of set hierarchy.

"I also ended up having to direct the movie via the chaotic clown director,/actor/producer/financier/studio head at the center. Yes that's all the same person. oh and did I mention he and everyone he had on the movie is in a cult. If I would've just formally directed it, it would've been much easier, but having to troubleshoot through his taste, ego and preexisting decisions made it so difficult".

Everyone in the business, especially those with experience as directors, should see this as a red flag, even if they believe Blake's version of events. And not get involved.