It should not default to ads, at least.

Very little of the content on the default start page is ever paid advertising. AFAIK it's a few of the Highlights, sometimes.

So they look like ads, which erode trust from users, and they don't even get paid for them. That just makes it more stupid.

They're mostly thumbnails of Web sites people have recently visited or visited frequently, i.e. they look familiar. I don't think they look like ads to most people, and I certainly wouldn't conclude they do without actual data.