Maybe it helps to understand it when you think of it from the perspective that those $1000 expenses do happen, they're not just hypothetical. But being able to cope with an event like that leaves you less able to handle a second one, and a third one
Couple that with the fact that I'm the US there is very little financial education so what might be an expected event for one person surprises another. Imagine living with a roommate and not realizing that to move into your own place involves coming up with first and last month rent, deposit, hook up fees, renters insurance, furniture, kitchen supplies, toiletries, etc... None of those should be unexpected, but also why would you expect them if you didn't happen to run into them before?
Basically no amount of saving accounts for an expense that takes it all, and it's then followed up by another one right after. And for some people those events are small and happen so quickly you never catch up and now you have late fees and interest and stress.