“If you give a man a fish, he’ll tape it to a broken ATM in protest. If you teach a man to fish, he’ll tape fish to lots of broken ATMs in protest.” - the wisdom of the elder humans

1970 was during the cultural revolution. In that year, the world population was 3.68 billion, and the population if China was just shy of 830 million - China had 22% of the world’s population, so if they held (only) 20% of the world’s prisoners, they’d have a lower than average incarceration rate.

The same is not true for the US today, we have less than 5% of the world’s population today.

Most browsers do this for certs with a lifetime longer than 398 days issued after 2020, which is one aspect of why so many websites use a 1 year validity period for their certs.