IMO, Google and similar require you to spend a lot of time preparing and training stuff you won't need to select for: a. hard workers, who will just do what is

IMO, Google and similar require you to spend a lot of time preparing and training stuff you won't need to select for: a. hard workers, who will just do what is required without fussing b. people who really want to work there, either because of the fantastic comp or because they drank the cool aid or they genuinely want to work on specific stuff that nobody else except the tech giants does. I agree that it basically hazing, and has similar purposes - it discourages from applying people who are not hard workers or just don't care about working at a FAANG that much. As long as they still get tons of candidates, it's a great initial filter.