Comment by ogurechny

You can try to guess the reason for such high temperature user boiling, it's not hard.

There is a single TOS and privacy agreement for all Google services. If you “just” log in to Chrome to synchronize history because “it's convenient”, you also allow everything else, including AdSense and other all-across-the-web tracking. By formally becoming a client, you lose most of legal protections against indiscriminate data collection.