Ofttimes people are sufficiently anti-ad that this point won't resonate well. I'm personally mostly in that camp in that with relatively few exceptions money seems to make the parts of the web I care about worse (it's hard to replace passion, and wading through SEO-optimized AI drivel to find a good site is a lot of work). Giving them concrete examples of sites which would go away can help make your point.

E.g., Sheldon Brown's bicycle blog is something of a work of art and one of the best bicycle resources literally anywhere. I don't know the man, but I'd be surprised if he'd put in the same effort without the "brand" behind it -- thankful readers writing in, somebody occasionally using the donate button to buy him a coffee, people like me talking about it here, etc.