Launch in US, page-163

Well that is an imaginative and very amusing analogy that makes me giggle, but it's not really accurate. The shares in a company aren't kombi vans or cars even, and they're less like physical objects than they were when they were certificates on paper. They're really just a priceable opinion of what a company and its prospects are worth. If markets mostly trade on emotion, which they do, then it makes sense to be able to take a negative view, and taking a short is the trade-able way to do that. They look like evil because they represent the fear that your hopeful climbing ever higher long trade may fall and it's a very understandable emotion to hate what you fear. The reality is that its just somebody betting against your view that a price will rise with the equally valid opinion that it might fall. To have a moral opinion that one side of a trade is more virtuous than the other is all in the eye of the beholder.