Because the green movement is largely made up of socialists. As such, the Venn diagram of the desired end result for socialists and the green movement is nearly a perfect circle. You will find very few right-leaning or libertarian greens. Almost all of them also believe in Marxism or some derivative of it, or at least some form of left-leaning technocracy. Hopefully you don’t need me to explain the relationship between Marxism and private property. And don’t assume I’m right-leaning per-say, I’m probably socially more left than you are, it’s just that I believe in the sanctimony of the individual (which is where my socially left leaning views stem from). I’m not even necessarily opposed to socialism in theory, just in practice.

To answer your second question, I don’t think it’s accurate to assume auto manufacturers have a financial interest in opposing the end of fossil fuels.