Try not to over-think it or stress too much about it. If you believe a hut is for humans, mark it. In prior campaigns, a "circle" fencing could have more than 1 dwelling inside it. Extended family live in groups.
If you believe the man-made item is a watering trough, corral or covering for animals, or likely used for another purpose, don't mark it as dwelling. Often, you'll see what looks like grains of rice inside an enclosure--- those are likely animals, or small size herd.