Pay to delete is dishonest, because the person offering to delete is taking money to provide false information. The dishonesty is on the part of the creditor, who probably has a contract with the credit bureaus promising to report only accurate information. In many instances, this scheme will work, but when you play with fire, you probably will get burned. Frankly, I believe you are better off creating positive information on your credit report instead of focusing on removing the bad stuff in the past. I published a 10 part series on credit repair explaining how the system works & have posted a link to the long list of all my articles. Unfortunately, you may have to scroll past many articles that won't interest you to find the ones that do. Hope this perspective helps!
Generally, paying a "charged-off" account will actually lower your credit scores because the credit reporting agencies will report the date of status as the date you paid. In other words, it makes it appear more recent in the eyes of Fair Isaac (the major credit scoring model provider). So, in this case, doing the "right thing" can and will usually harm you. It is also possible that the original creditor has already sold the account for pennies on the dollar to one of any large number of debt purchasers. Paying them serves the same purpose while they report inaccurate and incomplete information as a matter of doing business.
Pay for delete is largely a thing of the past. In light of the above, I really don't see anything unethical about it. The credit scoring system is unethical and frankly, illogical. You can try it, but most furnishers of information will say it's illegal - it isn't - and will deny the request.
Really, the only way to rectify these issues is to dispute the account tradelines through the credit reporting agencies. When the furnishers verify inaccurate and/or incomplete information, you sue under the FCRA.
I am not your attorney nor is any answer I may provide legal advice. You may contact me directly for legal advice only if you are a resident of Tennessee insofar as I only practice in Tennessee.