But the decision to operate the service or infrastructure 24/7 was a business decision, it wasn't my decision. Why should I be on the hook for a decision I didn't make? And if the business really, really wants 24/7 availability, why should that cut into my personal time outside of work? Why shouldn't the business set up teams in multiple timezones for a follow-the-sun model?

At the end of the day all this 'you need to be on call for your code' is purely a business money-saving ploy. We are an industry full of suckers, I guess, because we fell for the 'plausible-sounding' explanation hook, line, and sinker.