Standardized how?

Basically, there is no standard beyond the ages-old requirement to have abuse@ and postmaster@ email addresses that react to such reports. Which Google doesn't follow at all, you just get redirected to some useless web form which requires a Google account and the sacrifice of a goat.

It is entirely Google's fault, and they should be shunned for it and their emails dropped. But unfortunately, they are too big for that by far...

Maybe is thing about Gmail about "This message is spam", that is a Gmail feature not anything standard.

Same as Gmail broke IMAP standard, or Gtalk XMPP standard.

Google can do whatever they please, they've become the standard of humanity surveillance.