You're sidestepping the point of the article. Ivan Kirigin is not going to get screwed over by a website that asks for his Twitter password. But my mom might, because it is extremely likely that one of these fly-by-night Twitter add-on apps will lose their database to some stupid SQLI bug. My mom almost certainly uses the same password for Twitter and Yahoo Mail.

Moreover, each app that asks for passwords for another service adds social proof that this is how we build applications. It isn't.