It is commonly known that the effects of vaping are largely unknown.

Vaping is still ~9 years old. It would take several decades of prospective research to establish the effect/long-term effects of vaping.
Even still, so many studies released by institutions of varying prominence are coming out against vaping.
Here's one by the somewhat prestigious American Physiological Society that I recently read.

So I thought it would be important to discuss, Why so many haters?