It's easy to be very moderate with things which are not tasty, like... kale. If you eat too much kale, it can be harmful to you, but for some reason only a minority of the people have issues with too much kale.
However with carbs, it's extremely easy to eat too much and difficult to be moderate. At least for some, leaving out most sources of carbs completely has helped as it's easier to cut something out from your diet than to eat it in moderation.
I'm assuming it's the "bag of chips" effect. If you take one, you'll end up eating them all.
To me there are many bags of chips. Except kale, that doesn't have a bag of chips effect at all.
I know.
Just imagine if all healthy low energy stuff would have a similar effect?
"Wow I can't stop eating all this broccoli!"
If I were to be given a bucket full of bilberries (also known as the european blueberry), I could eat quite big portion of it. Well not all of it, of course, unless it's a small bucket, but it has a similar effect.
However bags of chips are cheaper and available all the time.