Because it's frankly the same thing, you're just defining one name for the people who do it well, and one name for the people who don't.

I work with extremely large data sets. Yay. I can call myself a Data Scientist to be in vogue and gain "competitive edge" with people who care about the name I call myself instead of what I'm capable of. I can emphasize that I didn't just "pick up" things randomly, but that I got an abstract mathematics degree. But I'd prefer to be known by what I can do, not my particular label.

"No, no I'm not a programmer, I'm an engineer, which gives me a competitive advantage!" -- Whatever, how well can you code?