I agree with your assessment. My point is just that search volume or user volume is an indicator of the size of the ad market, which is what any antitrust litigation will mostly be about.

They're not concerned with the user experience under these companies, they're concerned about economic impact, which is mostly felt by people doing marketing on their platforms. Facebook is a social media company the way the Yellow Pages was a book publisher - it may be the most visible product they make, but it's not how they actually make money.