I think he's being overly conservative out of fear of regaining the fat he lost.
OP, as stated before, I would suggest not looking at particular foods as good or bad. There are very few things that can be categorized this way at present (which is not to say that that public opinion on them may not change over time), like trans fats. Some foods are deemed as bad because they are calorically dense and people tend to overeat them, like pasta. Others are labeled as bad because they don't have a lot of micronutrients (vitamins and mineral). Yet, other are considered bad because they have nutrients that can cause problems for some people, like gluten.
Yet, these drawbacks don't make a particular food bad. It's the use people give the food what can be a good or a bad call, given a specific set of goals. For example, in the context of a fat loss diet, I believe there is nothing inherently wrong with eating some pasta, given that one tolerates gluten well and that the portion size is adjusted to meet one's nutrient requirements for the day. Some may disagree with this, but, in my experience, dealing with starchy carbohydrates, meeting macronutrient requirements takes precedence, given that one eats plenty of nutritious food throughout the day.