The main reason for this is that basic knowledge like that is needed to develop any sort of rapport between the healthcare providers and the patients.
Healthcare is most effective when patients trust the system. It makes them more likely to seek care and it makes them more likely to do what they are told by the providers. Such trust is hard to earn when the providers and the patients are from different cultures. It becomes even harder if the providers do not understand the culture of the patients. The providers can inadvertently act in ways that are deeply offensive to those from the other culture. If they do so, or if they act in less offensive, but still uncomfortable, ways they will make the patients actively distrust them. This will result in patients who do not want to seek healthcare.
A basic understanding like this is necessary, then, to allow patients to trust their providers and have a good rapport with them.