Most free web sites pay for their upkeep with ads. It has been an unwritten agreement since forever (or at least as long as there have been ads on the web) that if you consume the content, you pay the creator by looking at the ads on their site.
Consuming the content without looking at the ads is like shoplifting because you don’t like the way a store’s checkout counter works and/or the fact that they want money from you at all.
Definitely was one of the ones way back who said "If they keep it classy I won’t disable my adblocker. I want to say, generously, that maybe 10% of sites made ads that weren’t intrusive. Ad companies can’t handle themselves, they have to take over the entire page and distract from the content. It’s their own fault we use ad blockers.