You are right about Zoom management dumping shares right before an investigation of their privacy issues began. If not unethical it certainly shows an extreme lack of confidence about the company by the CEO a and other insiders:

https://www.thestreet.com/investing/zoom-vide...y-concerns

It is good you noted no Verb insider has sold any shares! That says something as I have not personally seen companies that did not have some Insider selling. I am sure there are some out there but it is not that common. In Zoom’s case the timing is suspicious and the amount of shares sold is large.