It's usually other companies wanting you to buy their shit, not the site that the ads are shown on. That site "makes its living" by selling ad-space to these other companies.
I dislike ads just as much as the next person but I feel like this representation is disingenuine.
However, it's up to the site how they choose to display ads, and UI/UX. If the content pane is like 1/4 the size of my screen, we're gonna have problems
If the screen had shouted "Buy this shit!" Would it have hit different? I had the same thought. I've seen a few sites that advertise their own wares and they are sketchy. I think the issue is that the site is still in charge of how much advertising they show. Usually, they're showing unrelated ads, but they're showing a lot of them.
I dislike ads just as much as the next person, and I'm just curious if I understand you properly.