Ads based on the subject matter isn't the problem. "Targeted algorithmic advertising" in this context is building a profile of the viewer, and running ads based on that profile.

At its simplest, it's the ad network deciding that you were recently seen visting toyota.com, so it'll show you 4 ads over the next hour for Toyota vehicles, to help cement that association. At its worst, it builds up an individualized profile over the course of months from thousands of websites (with google ads everywhere, you bet!) and allow advertisers to practically target viewers based on a psych profile.