Horizontal pulling exercises such as bent-over rows, dumbbell rows, seated rows, and machine rows mainly train the action of shoulder extension.
However, to strengthen horizontal shoulder abduction you need to add exercises like wide-grip rows, face pulls, dumbbell rear-delt flyes, or machine rear-delt flyes. The single-arm rear delt flye, shown in the video, also fits the bill.
Sometimes it's really interesting to dig into the microscopic details of training and nutrition, to dissect the body of academia and examine every little study. That's how we learn things. That's how we refine the science that later helps us get bigger and stronger and leaner.