I do not see why this service would be considered "unethical". Suppose your files get encrypted, do you want to deal with the ransomware operators yourself? Do you know where to get and how to send Bitcoins? Do you have a guarantee that your files will be decrypted after you part with the cash?
Here are your reasons to employ a middleman. Besides, what is so shocking in the fact that he identifies himself? Do you want a service from a real person or from some anonymous bloke?