The false dichotomy a.k.a. false dilemma is an example of black and white thinking i.e. everything is either "good" or "bad" with no shades of grey in-between.
On a popular body-building forum that I post on, I often see posts titled "Is *insert name of food here* good or bad?" I would like to grab the poster by the collar and give him/her a good shake, except that they are almost certainly bigger & stronger than I am and would "Smash me in" (an in-joke on that forum).
I've noticed the same effect elsewhere on the internet where certain things are deemed to be good (e.g. meat from grass-fed animals) or bad (e.g. omega-6 pufas). With man-made trans-fats, there's little doubt. They're bad!
Consider the following curve.
Just about everything food-related follows a J-curve, with amount on the horizontal axis and harm on the vertical axis.
Too little results in starvation/deficiency and too much results in obesity/toxicity. Even dietary carbohydrate can follow a J-curve. See Dangers of Zero-Carb Diets, I: Can There Be a Carbohydrate Deficiency? and Dangers of Zero-Carb Diets, II: Mucus Deficiency and Gastrointestinal Cancers.
The other problem with "good" & "bad" is down to human nature. People think that if "healthy fats" are good, then eating 10 times as much "healthy fats" is better. They also think that if too much sun exposure is bad, then zero sun exposure is better.
Like Goldilocks' porridge, there is a "just right" for everything. See Hormesis.