Why should not having a BS in statistics prevent anyone from properly learning and applying statistics in a rigorous scientific fashion?

There are a lot of people with a rigorous mathematical background (mathematicians, physicists, biologists, computer scientists, ...) who are perfectly capable of understanding and applying stats concepts at a high level. In addition, these people have a lot of experience with doing scientific research, so shouldn't they be even more qualified to call themselves "data scientists"?

Can you give an example of something that clearly distinguishes a "data scientist" from say a physicist who learned regression from a stats textbook?