This is 100% what it is. A "We went through it so you do too." sort of thing, combined with the fact that management can't interview everyone and SWE's aren't good at reading people to determine if they're lying.
I have a friend who's a manager at a FAANG and while there's a lot of good, smart people there, there are many, many people who are terrible at what they do and are very difficult to deal with.
My company does not do whiteboarding and makes an effort to get to know the person. We rarely get bad hires. Maybe 1 out of 100? Give me 10 to 20 minutes just to talk to someone and I'll tell you if they'll be a good employee. One of the first things I do is assess if they're lying on their resume. If they're not, then I'm comfortable believing in their skill set.
