This isn't a case of a company intentionally storing passwords in plaintext in their database. That's a big security no-no, because password hashing is such a basic and fundamental part password-based authentication that it's nearly impossible to miss if anyone involved in maintaining that system is remotely security-conscious.

This situation, on the other hand, seems to be more of an unintentional capture of passwords by their logging system. That's much harder to notice and more akin to a bug or security vulnerability, which is something pretty much every system suffers from sooner or later.

In such cases I'm more concerned with the company's response to the vulnerability than the fact that it exists at all. Here it seems like Facebook noticed the problem and proactively fixed it before it was exploited, which to me is a good sign.