Whoa, there - doesn't the fact that a low ranking employee, to use the phrase, can cause a global scale shitstorm, mean that just maybe, there are actually problems which were swept under the rug for too long?
Not necessarily. All that person has to do is tap into a controversial topic that divides people and involves the company.
E.g. "Big pharma researcher says our system is killing people." If it wasn't already done and old news, if it happened to get traction we'd have the same situation. And let's not kid ourselves, he's probably not the first there to state this or even the first to share his views. He is the first that had it turn into big news because it went viral, but content isn't the only factor in something going viral.
Some of the later claims of the low-level employee absolutely justify the dumpster-fire: if diversity-related meetings go deliberately unrecorded to stop paper trails, if special second-chance privileges are given to diversity hiring candidates, .... that's pretty rotten stuff.
Well, more specifically, I think he was fired for being political in a way that caught outside attention and caused bad PR. Plenty of people are political at work, whether they be work politics or otherwise. This is a "You made the company have to weigh in on something that is way over your pay grade, and that's not something we're going to take a chance happening again with you." Executives and boards don't like when they have to stop what they're doing and put out a PR fire started by a low rank employee, whether that employee expected that outcome or not. That the firing of the employee causing problems at the executive level coincides with a way to combat the PR just makes the decision all that much easier.