Ok... but that's exactly how it's used. With the Google Safe Browsing API, you're sending the URL and other data in to be validated if it has certain marks of suspicious webpages and is not present in the database.
...and it isn't Hashed like other databases, so Google knows exactly what you're looking at.
Google Chrome Privacy Whitepaper
www.google.com
"Chrome will send an incident report to Google every time you receive a warning, visit a suspicious page, and on a very small fraction of sites where Chrome thinks there could be threats, to help Safe Browsing learn about the new threats you may be encountering. Additionally, some downloaded files that are suspicious and show a warning may be sent to Google for investigation each time they are encountered. All reports are sent to Google over an encrypted channel and
can include URLs, headers, and snippets of content from the page and they never include data from browsing you do in Incognito mode. If Chrome discovers unwanted or malicious software on your machine, the reports may also include details about malicious files and registry entries. This data is used only to improve Safe Browsing and to improve security on the Internet."