Google aren't subpoenaed

Perhaps this is the difference, some people are concerned with being anonymous from companies like google, amazon, etc. Some don't mind that, as long as they are anonymous from a government.

Your mention of subpoena suggests you don't care about google tracking you.

Google gets subpoenad all the fucking time. They have whole departments set up to handle the case load.

Some public evidence: https://www.alphabetworkersunion.org/press/google-lays-off-c...

I was directly replying to someone saying they could subpoena the temporal owner of an IPv6 address, as though that were somehow different than IPv4.

The tracking is a moot point. You can be tracked using the same technologies whether you connect though v4 or v6, and neither stack has the advantage there.