> Are e-cigarettes regulated by a governmental agency to ensure that they only include listed ingredients?

No, but they should be. No one is arguing that quality control isn't important. The problem is that the debate is being marred by FUD that would seek to remove access to these devices for people who need them to quit cigarettes.

> you in reality have no idea what ingredients the Chinese manufacturers are putting into their vapors

Aside from the gas station disposable ones, most e-liquid purchased in the US is made by small local businesses who want to do right by their customers. I certainly would never buy e-liquid from a non reputable vendor, and certainly not an anonymous company in China.