Any kind of concentrated sugar product is going to be unhealthy regardless of the process that got it there. Fresh squeezed orange juice and honey aren't refined, but they're still much too sweet to be consuming large quantities of.
If your concern is obesity and diabetes I encourage you to look up fruititarians. They consume 3000+ calories a day of fruit and loose dangerous amounts of weight. It's not healthy to consume such low fat and protein but it goes to show you can't gain weight on fruit juice.
Conjecture: it's sugar and polyunsaturated fats at the same time that cause issues.
squeezing juice out of an orange is a level of refinement. You are reducing a whole food to separate components, much like pulling iron out of ore. It's weird to think of it as a refined food but it is to a degree.
I wouldn't classify it as a processed food, but maybe that's where people conflate the terms.
sugar in a whole fruit aren't bad, the fibers in the fruit help your body break down and absorb the sugar over a longer period of time.
just don't eat refined food.