We are for ourselves, but that does not exclude we cannot be helpful to other at the same time. Someone produces clocks, not just to his benefit, but so that he gets profits, and so that others can enjoy the clocks. The utility of many people can be thus increased.
We work together because we can, and we know it benefits all of us. Markets are based on voluntary participation, no one forces you to work. You just choose to work with others because the benefits happen to be quite large. You could also very well live alone in a cottage in the middle of woods farming alone and hunting alone. But most people participate on the markets out of free will. THERE IS ALWAYS THE CHOICE NOT TO PARTICIPATE. That is what too many people never realize in their hatred of free markets.
Why would they live on the streets, if they have labour to sell, for which they will be paid, and thus allow them to gain housing? Only state can limit the possibilities of employment, so under properly free competition models everyone who wants to sell their labour could be employed.
Companies consist of people, people with morals. They follow certain patterns of action, and most of them are good people. Yes companies exist to make profit, but they also do much good. Isn't the utility of your life now greater that you can use a computer someone produced, linked to internet someone produced? Or do you despise computers and hate the corporations that force you to buy such goods?
Your arguments are mostly overly negative nonsense, people are still not selling their souls. Markets are based on voluntary participation. That is the core idea of a libertarian system. Free will, freedom of choice. No state forcing you this or that way.
Now about consumer theory, something that you probably never have understood. Companies exist to serve the wishes of the consumers. The consumer reigns supreme. Once the consumer gains knowledge that certain company is bad, they will choose to limit their consumption of goods that the bad company produces. If the company faces bad sells, it either reforms, becomes more 'good' and 'just', or faced with long term negative revenue, simply goes bankrupt. All companies serves the whims of the consumers, who are merciless and very rational.
If a bad company operates longer than it should, blame the consumers that keep it afloat.

And there will be always individuals that are out there to spread knowledge about the misdeeds of 'evil corporations'.
I wrote a long post about charities earlier on this thread, cba to repeat it word by word.
Evil is the absence of good, that normally fills us. Men become evil only under dire times, and even then their evil actions are still very relative in comparison to good times. Some actions will be necessary for the survival of the body. But the majority of the time, the majority of people strive to do good. We are programmed by nature to work for the benefit of our tribe/pack, as long as it also serves our individualistic needs. Basic knowledge about behaviour of animals that live in packs.
Read too much Nietzsche?
Mankind always strives for the best possible outcome, erring along the way, with the ultimate amount of good as the ends of the entire race of man. If you refuse to believe otherwise, you can return to your cave of nihilistic philosophers and abandon the teachings of biology, psychology and economics.
Have some faith in mankind Dadarian.