Identifying a Logical Fallacy in a Health Discussion

Alice and Bob are discussing the importance of exercise. Alice asserts, "If exercise was really important for your health, doctors wouldn’t prescribe medication to improve health." Bob replies, "That’s not true. Doctors prescribe medication for people who can’t exercise due to various reasons, like injury or illness." Alice is committing a logical fallacy when she implies that because one treatment exists, the other must be less important. What kind of fallacy is Alice demonstrating?