The judge, a human who possesses common sense, sees you've registered lots of domains and spammed C&D letters to Google, calls you out on your BS, and orders you to pay Google's legal fees?

In Switzerland this would be «manifest abuse of a right». https://www.admin.ch/opc/en/classified-compilation/19070042/... (art. 2 paragraph 2 of Swiss Civil Code: Acting in good faith).

This is a common standard in many jurisdictions and an important element of the rule of law, so I think that in the US, if law is done right, a judge will identify such behaviour as abuse.

CFAA: "Whoever having knowingly accessed a computer without authorization..."

I am not a lawyer, but accidentally violating the cease and desist would clearly not be a breach of the CFAA.

And in any case, civil suites are designed to compensate you for damages. If Google's acts caused you no harm, then you wouldn't get anything even if they were in the wrong.

If you yelled at a deaf person to go away, are you surprised that they don't comply?

robots.txt has no legal standing by itself, but is a convenient way to translate "terms of service" (which do have legal meanings, but they're often more limited than people assume) into something that bots can automatically understand. You're under no legal obligation to follow robots.txt, but it's a tool to prevent stepping on toes.