Refined sugar is not inherently unhealthy.
Consuming refined sugar is inherently unhealthy because it’s consumption causes insulin spikes and eventually insulin desensitization which leads to diabetes which is a strong predictor of inflammation. The same logic applies to any refined foods with concentrated amounts of fat or salt.
No whole plant-based food has the concentrated amount of macronutrients that are in processed food. You could argue that honey might be one, but honey’s been refined from pollen by bees.