I've spent most entire career at relatively small companies (25-100 employees). I've never seen these types of issues (I can't say they've never happened, I'm just not aware of any). In fact, reading these stories is probably why I've never had the desire to apply to work at any of the large tech companies. I can't say for certain what the differences are, but I think smaller companies tend of have less office politi…
Smaller companies, from what I've heard, have tons of office politics problems. You hear about it less because most small companies have no national importance, and thus do not excite the press the way a large company would.
I would almost be willing to guarantee you that an incident of gender or sex discrimination has happened at one of the companies you've worked at, at least supposing you've been working more than a year or two. Just because you didn't hear about it doesn't mean it didn't happen. These things are generally kept pretty quiet -- splashing them across the headlines is the exception, not the norm.