Actually, this is scientifically wrong.
The myth that artifical sweeteners are a bad as sugar has been disproved some time ago.
For the harm, e-smoking may pose, one cannot really tell. However, the sole intake of nicotine is not as harmful as smoking tobacco. This difference is mostly due to the presence of MAOI in tobacco.
Citric acid actually is worse than phosphoric acid, but how many sirups are made with citric acid? Also, if you limit your intake, you should be fine. Alas most juices comprise in part of citric acid.