A side effect of ads (and something that ad blockers mask, giving websites a normal appearance) is that ad supported websites have the wrong incentive.

When you browse a website with no ads, you are the public. Content is provided for your use, and that's all.

When you visit an ad supported website, you are only the means to achieve an end, which is to have you in the site as much as possible, clicking on as much ads as possible. That usually had the effect of making the website content bloated.

Not all sites begin like that, but they all end like that. And ad blocking hides that ugly truth under a layer of normalcy.