[derefr]

Google says they explicitly don’t use web-browsing data for ad targeting. They don’t say that they don’t use web-browsing data to improve your experience with their various recommendation/prediction/autocomplete APIs. So there’s no guarantee that bad ad targeting implies YouTube doesn’t have a better profile on you.

[polyomino]

I’m order to square these requirements, they would just have to use your browsing data to target you with the version of the instructional video which always plays relevant ads to you

[derefr]

From what I understand (someone correct me if I'm wrong), the selection of ads that play on an individual YouTube video aren't actually affected at all by which video you're watching—only YouTube's understanding of you built up over all the videos you've watched so far.

[beojan]

The sponsorships are part of the video. They are targeted only by video.