So, to take it to one extreme, you think that if zero accounts were accessed, then it would be reasonable for zero users to be directly notified about this?
Some people might also be concerned that the note about sending emails wasn't added to the post until after there was mass outrage at the lack of notification. Makes it feel very inauthentic, as though they were really hoping they'd be able to sweep it under the rug.
That doesn't sound reasonable in the least bit.