I think this part of the article directly addresses your complaint: "I asked Andrew Vickers, a statistician at Memorial Sloan Kettering Cancer Center, to take

I think this part of the article directly addresses your complaint: "I asked Andrew Vickers, a statistician at Memorial Sloan Kettering Cancer Center, to take a look at the analysis. He said it wasn’t surprising that there was an association between e-cigarettes and smoking. The real question is how big it is. While this study suggests that the effect is large, Vickers found reason for caution in what statisticians call the “confidence interval,” a plausible range of values for the study results. The confidence intervals here are “ridiculously wide,” he said, which means that the estimate that e-cigarette users are about eight times as likely to take up smoking as non-users is just a rough approximation — the true increase in risk could be anywhere from 30 percent to 5,700 percent."