Hacker School is not a random website where you throw up code to have random strangers look at it. It is a three-month-long "writer's retreat for programmers," where you are sitting and working with other developers every single day, just like in a workplace, except that you're working on what you like and won't be fired.
Code reviews are in person and could easily become unprofessional or attacking--but they don't because there are very strong social rules about how to conduct them effectively and with improvement in mind rather than criticism.
I respect the point about thoughtfulness vs personal experience, but you should at least make the effort to look up what Hacker School is before making comments about it.