This may be a terrible analogy, but skeuomorphism is to realistic lighting/textures as dubstep is to Skrillex.
Many people think that, just because it has some leather texture, it's a skeuomorphic design. Skeuomorphism is all about trying to re-implement a familiar interface or object in the digital world when it may not necessarily be the best decision from a usability standpoint. It's often an attempt to translate a physical object into a digital representation with no regard to differences in interface.
Just like some people think all dubstep is like Skrillex. He's the most recognizable artist, but all the term dubstep means is that the music is of a specific time signature. It's a syncopated rhythm and normally falls between 138 - 142 beats per minute.
YES. This article is a great place to send people who think realistic lighting, gradients and shadows means skeuomorphism.
I feel that Gruber's post on Skeuomorphism is a bit off the mark. This is a great piece all about what Skeuomorphism really is. It isn't a bad thing, it's just a thing.