What I observed was a discussion of 2 as if it were not really simple.

Would you mind linking to an example so I can understand what you are talking about?

If you make a rule saying you'll not eat carbs, you'd be hard-pressed to come up with enough calories eating non-carb stuff to not lose weight.

That may very well be the case. I myself am pretty skeptical of low carb dieting. At a minimum, it does not appear to be the "silver bullet" which some people have claimed it to be.