A lot of new construction painters are not the most conscientuous. I've seen guys go through with sprayers prior to cleaning the sub floors and just blow floor debris all over the walls along with the primer/finish.
I would take some eighty weight paper and sand them down. You might use a sanding pole, but I think it's more effective to take a full sheet of paper, fold it in four, and go to town by hand. Now you're right on top of the wall where you can sand and feel your results as you go, and you can adjust the pressure to what's needed. A sanding pole keeps you at a distance. Whenever you're sanding anything, one hand sands and the other is constantly feeling for what needs sanding and the results you're getting. IMO, a sanding pole is good for general scuffing and hitting here and there spots without the need for a ladder, not this type of work.