I bought some of them a few years back and the paint on "Canon" rubbed right off. Piece of crap.
I'm fairly sure the Canon logo does not substantially add to it's ability to protect the lens.
Did the cap itself stay in place and do it's job, or it didn't do that either and hence the POC rating?
A third party lens cap without a logo can easily be had. However, if the reasons for buying one also include having the Canon logo on it, then it fails miserably. Ergo, it's a piece of crap.