I hate linkbait headlines like this because DUNS is not a scam: It's a useful tool used in the real world of business. Need to see how long a company typically takes to pay? You use DUNS. Want to get and Federal work? You have to have a DUNS before you can register (in addition to your IRS paperwork). Of course I get the idea that if you're a lone coder how that can be a pain. I also get that if you aren't in the US…
I think the real problem here is trusting ratings organizations to objectively "rate" companies when they have an incentive to extract money from those companies.