Should I include a recommendation letter in my MS applications if it is not required?
Generally speaking, any material that is not asked for will not be considered in an application for a postgraduate degree. Admissions procedures attempt to create a level playing field for applicants as well as minimise the amount of time it takes to evaluate an application, and extras that aren't asked for are tossed in the bin. Some places may treat that material differently, but you asked for general.

Now speaking specifically, I would be surprised if you were not asked for recommendations during the admissions process. The line you posted does not preclude recommendations, rather it might reveal what elements of a recommendation letter they will pay attention to. You need to either start the admission process online and see what documents you are asked for or call the admissions office for clarification.