And the majority of those women who are 'justifying unhealthy binges', as you put it, absolutely ARE doing their best to eat healthily during their pregnancy, and other times. But they are doing it in the context of everything else that is going on in their lives as well.
What to eat and when and how much of it is almost never an isolated, simple, free choice. It is affected by income, free time, stress, health issues and limitations, pressures from people they live with or work with or care for, their lifetime emotional relationship with food and eating - the list goes on.
Just like, every day, people choose the lift instead of the stairs (for all sorts of reasons), grab a ready meal instead of cooking from scratch, have to choose between heating their house instead of eating fresh food, or choose to buy something 'unnecessary' that gives them a little lift in spirits rather than buying something 'worthwhile' or donating the money to charity.
Noone is having the same day as you. Noone is having the same life as you. If you find it straightforward to live within the 'ideal' parameters of vegetable intakes and BMI that's great for you. It's not straightforward for lots of other people. There is no moral failing in that.