Quick food for thought....how many of those now ecig users used to smoke? We know smoking causes cancer. So instead of blaming the previous use of the thing known to cause cancer, they blame the new thing. That's just....silly.
Correlation does not equal causation, but it's an easy logical fallacy to fall into. Happens all the time. Take Tetanus for example. Ask a bunch of people how you get Tetanus, you'll get a lot of "stepping on a rusty nail" replies. It's true, stepping on a rusty nail outside is a really good way to get Tetanus if you're not up to date on your shots. So what can we take from this? That rust causes Tetanus? It's a logical jump that a lot of people make, one that's been perpetuated for decades, it's also COMPLETELY false. Tetanus is a bacteria that grows in dirt. Where do you tend to find rusty nails? Outside, in the dirtyness that comes with being outdoors. Rust had nothing to do with Tetanus, nor do nails. It's just a convenient opening for the bacteria to invade, should you step on a rusty nail....or piece of glass, or manage to get dirty in an open wound through any means.
Anyone can be guilty of making a completely wrong logical jump. I bet a lot of people on here thought that rusty nails caused Tetanus. I wouldn't condemn someone for being misinformed. I'd condemn them for being uninterested or unwilling in finding out the truth, or consider that their reasoning may be flawed.
We take for granted that doctors are a step above the rest of society; that they aren't at risk for making the same logical fallacies that the rest of us are prone to. That's just not true. Doctors are just people, they aren't necessarily smarter than any random guy you could point to on the street. They're just....people, and people, as a general rule, are stupid.