I think it's really a prejudice sort of thing, really...   If someone has that thought in their head, it will probably stay there.

There are many definitions of art, everybody has their own.  Many people only think that paintings and/or sculpture counts as art.  That means that metal smithing, textiles, even music are off the list.

I think what it really comes down to...  Does the work move you?  Does it make you feel something?    "You" in this case really has to be the artist, because it's the artist's expression, not how it's interpreted that matters.  (On the other hand, you could make a render that you feel is just an exercise, while it may really strike a chord with someone else...)

With that said, of course, I can say that not every render I've made would I call artistic.  Maybe a couple of them though...