I am curious - where do you work?
Asking so that I can potentially avoid that company, as this is the most inane and borderline backwards thing I've ever seen written about senior engineering.
In some startups, everyone above 25 is senior developers. Everyone else is junior, there is no middle role. So it is not like companies had much choice how to label people.
Imo, most of what people write about "senior engineering" is what they personally admire in this or that senior, what they aspire to be or want others to be. It is not what actually role labeled "senior developer" is.
That being said I agree I wouldn't want to work somewhere like what was described above. It's certainly not a style of interview I would approve of or conduct myself.
If the anecdote is related to your experiences working on FB then, please, specify it, blanket statements aren't what I expect from HN comments.