Has the cat shown an interest in the scratching post before?
I have found that it takes a little effort to get them trained to use the post. Take them to it. Play games with a catnip mouse on top of the post (better have quick hands!). Reward them when they use it. And so forth.
Mine have flat worn out a sisal rope scratching post. They love it.
It is just fine...all cats have weird little "ticks". Your cat just happens to like having his nails filed. My Sport like it when I take his toes and play "this little piggy went to the market"...if you can beleive that. You are not harming your cat...just be careful of the "quick", do not file too far, but other than that it is fine.
Maybe try a different material? Hennessy isn't too sure about carpet (and I avoid it, not teaching a bad habit if I can help it) and he's rather blaise about sisal, but he LOVES that cardboard stuff... But! It has to be flat on the floor so he can sit on it and really get up a good head of steam. Try a lot of different types/placements... I'm sure you'll find something kitty likes.
I think it's kinda cute I don't see why there would be anything wrong with it.
Chloe (my cat) has definite preferences about what she likes to scratch. She won't use cardboard, only sisal. She loves vertical but will use the horizontal one on occasion. Thankfully carpet isn't her thing.
The key to sisal posts, for me, has been enticing the cat to climb the scratching post. Once I've gotten them to climb it -- usually to get a toy (or my hand if I'm too slow) -- they have started scratching it.
Once they start, they seem to have a nice stretch and scratch every time they walk by.
Now, I'm trying to get them to use a new one, rather than one they've mauled to death (literally scratching through the thick rope!).