As someone who has spent a lot of time around startups, the amount of employee turnover was one of the craziest -- indicative in hindsight -- things in John Carreyrou's extremely well-reported book, "Bad Blood." Most startup boards would have looked at that level of employee turnover and realized that there was something much worse going on than a young founder without much management experience doing a poor job at hiring and retention. But the board apparently didn't get very much information about the actual operation of company, didn't push for more, and didn't question or dig into what they did get.
I'm willing to forgive quite a bit of "fake it till you make it" flim-flam, but anybody who uses such strong-arm tactics deserves having the book thrown at them.