Here is the rationale for using Google as the default for ntp which appears to be a problem with ntppool.org than any supposed favouritism for Google. https://github.com/systemd/systemd/issues/16148

However I was under the impression an OSS project could use *.pool.ntp.org as their default but was preferred that they get a vendor zone.

https://www.ntppool.org/en/vendors.html