Is it having to pay, or the hassle of having to set up payment that's maddening? If I knew clicking on a link to an article I believed was worth reading would cause my credit card to be charged a few cents, I honestly wouldn't be bothered at all. But I am bothered by the hassle of setting up an account (often with some significant minimum spend, or ongoing subscription you have to remember to cancel), filling in my details, worried about whether my payment details are being stored safely etc. etc.

People who don't want their website to be a 100% loss? I hate paywalls too, but the alternative is so many ads you can't find the article.