Pretend there is a Museum. It's free to the public with a suggested donation. You go there every weekend because of it's interesting collection of $thing. You never pay the suggested donation.
Is this ethical? It's not illegal. But that isn't the question.
Not a good analogy. If there was a donation mechanism, many people might choose to pay it. I contribute to several sites via Patreon, for instance.
But if every time you visit the museum someone follows you around talking in your ear about the products available in the gift shop, you might choose not to go, or (if the content is interesting enough) you might start wearing headphones or earplugs and go anyway.
