So McDonalds is ok because it is at least somewhat restrained by the need to offer a useful good (food) but the financial industry is parasitical and evil and offers nothing of use? Seriously?
McDonalds would do anything to squeeze more money out of its customers. Like most corporations, they profit from manipulating the human masses.
Sure, you can argue all day against the usefulness of speculative speed trading firms - and even then you'd still have some decent arguments against you - but to argue that financial institution in general offer nothing of use is ludicrous.
Some relevant quotes:
Corporations are at least somewhat constrained by the need to actually provide some service that is useful to people. Exxon provides energy, McDonald’s provides food, etc. The exception to this seems to be the financial industry. These institutions consume vast amounts of wealth and intelligence to essentially no human end. Of all human institutions, these seem the most parasitical and dangerous.
it [the financial system] has interests that are distant or hostile to human goals
"Utilitarianism is a theory in normative ethics holding that the proper course of action is the one that maximizes utility, usually defined as maximizing happiness and reducing suffering."
He sees financial institutions as a waste, and therefore consuming vast amounts of resources to no useful or positive effect.
Finance firms provide lots of very sophisticated ways for money to get from people who have lots of money that they don't currently have a use for, into the hands of people who have a need for money they don't currently have.
Note this is a weak claim. I'm not saying anything about the efficiency of this process or whether the financial industry is good or evil or anything. But you can't criticize the finance industry without at least understanding and engaging its outputs.
The argument I would like to make is not that finance is bad intrinsically - as you've said above. The real problem is that the current instantiation of this concept has grown a series of goals of its own, and to fulfill those goals it is doing things that use the common, shared, limited pool of resources of the global economy, siphoning off stuff that the rest of us could put to better use.
In other words, they could perform useful services for us, and they do. It's all the extra layer on top of that that's the problem.
In a strict, mathematical sense, the OP probably exaggerated when saying they are entirely parasitical.
The financial industry is as evil as any profit oriented industry can be and to single it out as something completely wasteful and parasitic is unreasonable.