Like I said before, the difference is that carbohydrates are necessary to simply function, to sustain life. That's the difference between caffeine and food.
I'm open to debate on this, but calling a person a "virginal" purist, as a previous poster so eloquently put it, is silly. That goes nowhere.
And I agree that there's a legal line that has to be upheld. But still, using a known performance enhancing substance, legal or not, violates the spirit of the law. And I find it extremely hypocritical of Wejo to be sooo hard on dopers when he himself knowingly used a PED. His justification is even the same as every other doper ("Everybody does it, it's not harmful, blah blah blah").
Last season I decided to use caffeine for my final 5k of the season. I'd already run some decent times that year, had read a lot of the debate on caffeine, and was curious how I would feel racing on it. I pr'd from 15:16 to 15:04 with a huge negative split and a 66 last lap. I'm not a sprinter (55 quarter speed), but went through the first 200m of that final lap in 32 and slowed the final 200m only because I dropped my opponent. I felt a m a z i n g through the entire race, and felt so fresh in that final mile.
If I'm not talented enough to approach 15:00 on my own work and training, why should I feel good about using a drug to get me there? Well, I don't. No amount of justification can erase the fact that I simply was not good enough to run that fast on my own.