He could have gone to a tube site and gotten similar content for free. Instead, he's a paying customer who chose your site over countless others.
If it were me, I'd not only give him his refund, but apologize and even offer a month's free access to another of my sites that might be more to his liking. Set yourself apart from other sites with a high level of customer service. Hey, if the guy likes what he sees on the other site, he may even return as a paying customer... though if he asks for a refund again, you know he's just a scammer!
I agree with him that it's a little distasteful, but there are fans & haters of every niche.