I'm pretty sure it is using pure DNS recursion, so if you ask for abc.google.com, the pi itself will ask the com TLD DNS server for google.com's DNS server, then go and ask google what abc.google.com's IP address is

So you're not asking the ISP for abc.google.com, but because they provide the internet, the ISP will see all your requests, including the UDP request to the .com TLD, google.com's DNS, etc