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.
Jumping a turnstile is less theft than adblocking. That subway train is gonna run whether I’m there or not. On a site, you are more directly consuming their resources.
In any case, due to capitalism you can’t give companies an inch cuz they are required to abuse the shit out of it to squeeze out as much money as possible. It’s not enough to show an ad at the start of a YouTube video, now you have to have multiple unskippable ads at the start and also in the middle of it too. And that’s not enough either, now you gotta track people across websites, even if they aren’t logged in, to show more ads. And that’s not enough either, now you gotta sell user data because if you don’t, you’re leaving money on the table. It’s gross.