The reason why dried fruits are high on the list is due to their high sugar content. As far as regular fruits go, avoid mangoes and bananas, as they tend to be high in sugar content. Sugar has a tendency of making diverticulitis worse, or causing diverticulosis, which is the beginning of the condition where you might not yet experience symptoms.
As far as whether you can still add it to a regular diet now and again, you can still do so. Dried fruits, while on the list of foods to avoid, are not the worst offenders. They are high in natural sugars, but moderation can help ensure you do not suffer the symptoms of diverticulitis.
Those who suffer from diverticulosis typically experience no symptoms until the growths get inflamed, which is the reason why some people get carried away with sugary snacks. Be wary of what you eat, especially if you have diverticulosis. As far as regular fruits go, you’ll also want to avoid the ones where you end up eating the seeds as well.