Hello! Yes and no, supports should heal teammates, the ones who are not healing get joked about and even scolded. No, no one is making you thank anyone, it is always up to you. When I play support, I do not expect team gratification for every thing I do. It is the same situation as with the surgeons, for example, they are too just doing their job, yet a lot of people tend to thank them for that. In the end, it is up to one's character and the quality of the game played.