Sugar consumption is safe. The problem is that people over consume the wrong types of sugar in highly palatable foods. The same way in which an extremely high fat diet is bad for you, especially if you eat the wrong sorts of fats.
A whole generation was also taught everything in moderation, but we've not been very good at it.
I think that video is more helpful for you than it is me.
"He argues that fructose (too much) and fiber (not enough)".
Too much sugar is bad for you, too much fat is bad for you. If you eat too many foods that are high in processed sugars, you're going to increase your risk of diabetes. If you eat a balanced diet that includes fruits and other complex carbs with fibre to reduce the GI of the food, you're going to be fine.
All of this needs to be combined with some exercise.
This isn't ground breaking science, this is a Youtube video for people who have a poor diet.
A whole generation was also taught everything in moderation, but we've not been very good at it.