Almond and coconut flour are likely to have more (natural) sugar in than wheat flour. Bread made with coconut flour in particular is surely going to have more total sugar than regular bread with a little added sugar.

A more reasonable explanation is that the comment that triggered this discussion was just from someone who used the wrong word by accident or totally misunderstands what carbs are.

The gut doesn't absorb sugar as well in the presence of fibre so I think people tend to subtract the amount of fibre from the total carbs to come up with something called net-carbs. No idea how well this works in practice of course but there is definitely some high percentage of sugar not absorbed for every gram of fibre added.

I'd say at that point just give up on eating bread. Something bread-shaped and fluffy could be made of anything.