Well, auto racing used to be in part about building better cars. Until the turbine came along. Now, turbines and 4-wheel drive are banned at the Indy 500.
That's utter nonsense. You might as well bitch that IndyCars aren't allowed in NASCAR races. Or that sticks with more than 1.5" curve depth aren't allowed in the NHL. Or that metal bats aren't allowed in MLB. Or double-strung rackets in tennis.
Every sport has rules and limits, often for safety if nothing else. If you don't think race teams have teams of engineers trying to make the car a teensy bit faster and a teensy bit better at holding speed in corners while staying within the design rules, time to think again.
Back to human doping: I won't disagree that there's a fine line between PEDs and legal stuff like high-protein diets and a few cans of RedBull. And for that matter, the kind of diet (both type and quantity) that NFL players eat does in fact have ramifications for their long-term health. I think the difference is (supposed to be) that banned doping substances are radically dangerous even in the levels in use, let alone overdosing.