This ad has succeeded to the extent that it's getting pretty popular on Hacker News and (hopefully) it's attracting the types of programmers they're out to hire.
Assuming that they've got their 'ideal hire' right, it's almost a win-win situation for them: if you hate the ad, you probably don't like their culture; if you love it, you'll apply and you might just fit right in with these "ninjas".
It alienates some but at least not the people they're trying to hire. I'm not saying such a culture's going to be great for them, just that posting such an ad will get them exactly who they want, and some mad publicity as well.