Some people have bigger [data] appetites than others. Would you be in favor of a rule against fat people or really wired skinny people? And the shopping bag analogy is rather broken: if you were paying for 24/7 access to a buffet it wouldn't matter if you walked out with extra food to eat yourself.
(I'm ignoring any kind of food/bandwidth resale, I don't object to that being outlawed by the TOS.)
A fat person may eat 2-3 times what a normal person does. Not 10,000 times. The analogy is about abusing normal expectations. You are trying to make it fit too tightly. If you really want to extend it to 24/7 access to a buffet it would mean taking up all the plates/silverware so no one else can eat there. Then becoming indignant when asked to leave 'you said it was unlimited!' But I have no desire to play analogy ping pong.
Someone that uses a lot of bandwidth isn't doing it to be a jerk. And if they inconvenience others the network is frankly set up badly. Normal users will saturate a connection some of the time, and networks need to handle it. And if a network can handle saturation for one hour without problems, it can handle saturation all the time without problems.
The only way you could sell flat rate unrestricted internet service is to increase the price and force your most profitable users to subsidize your least profitable users (biting the hand that feeds you). Bandwidth usage based metering would help fix this, but there is an extreme aversion to usage metering among even low usage customers.
From a (former) network engineer's standpoint: people who are upset that they can't keep their $50/month 20Mbps connection at line rate 24/7 make me think of people who want to fill shopping bags at a buffet.