"Unfortunately, most people are actually thinking of, and referring to, carbon dioxide when they think and say carbon in relation to the environment."
That's because carbon dioxide is the primary target of "carbon concern" relevant to the climate change topics.
People don't have to constantly be super-specific in everything they talk about, when there is sufficient general context around what they're saying to reasonably expect others to understand what is meant. Clarification can always be asked for and provided.
And, rightsideofhistory, you're a dumb-ass for reading too literally and not for comprehension - WAKE THE FUCK UP
Plants respirate carbon dioxide and oxygen (the former in, the latter out), and its absolutely true that more carbon dioxide in the atmosphere helps plants flourish.
The point made is simply that carbon dioxide is NOT the evil pollution that the climate change nazis claim it is, and that such insights are often obvious via numerous common-sense observations.