These companies attract hyperanxious and/or hypercompetitive types (among many others, e.g. the hyperdeluded "save the world" types, the hypermaterialistic "drive to work in cars worth 6 figures" types, etc). You don't accidentally end up in a big tech job. Most people have to grind leetcode in order to get into these companies -- you know full well what you're getting into. Your offer letter may actually state "people come to this company to do the best work of their lives".