Well at least this one can't be blamed on the TSA...

Note: for the uninitiated, "TSA approved" does not mean that the TSA has taken the lock to some mysterious TSA lock testing laboratory to determine the effectiveness of said lock, only that it can be opened using a TSA key.

Clearly this is a case of some manufacturer finding a way to get useless locks made for a few cents and branding them as a high-quality, "TSA approved" lock for unsuspecting victims to purchase.

But a question for the OP - was this lock in a sealed, opaque container when you bought it? How did you only notice its uselessness after purchasing it?