Tell that to an H1B holder.
You're not wrong to point out that we can't generalize from a single data point, but you're wrong to bring your positive experience as if there is an equivalence between the two. They don't have the same weighing; we are not trying to have a 50:50 split between bad and good experiences. Even a single workplace-driven mental health incident is too many. And unlike other workplace related injuries, mental health injuries are elusive to tracking.
One hard metric would be the percentage of FAANG employees that are lost to suicide each year. It would be morbid but telling if some companies have an overrepresentation (I have my doubts but won't voice it here).