Shinzenbi said:
One of the things I hate the most in life is business. It corrupts everything it touches. A friend who also runs a business said “Business is a shame, everyone wants to f… you”. Not a very nice way to put it but I confess that I agree. Business appears to me as the very opposite of the natural human values (not to say that in its current capitalist form, it carries in itself satanic antivalues).
I agree that business as it is usually done today is of a negative nature. It is carried out as to maximize profits without regard to the effects on consumers, workers, other businesses and society in general, as well as in the sense that business owners have to conform to the market in which they plan on doing their business, which includes being subject to loans and financial products, abusive taxes and regulations, the likes and dislikes of brainwashed consumers, having to compete with the ruthlessness of big corporations etc.
Being that we are in a STS environment where the social and economic structures are imposed from the top, including through laws, regulations and business practices of the Big Oil/Pharma/Agro/etc, it is understandable that the common man who has a heart and does not want to profit on the misery of others will be in struggle when he is caught on this negative chain of events.
I'd add that this system is detrimental not only to the common business owner but to the employees as well.
However, the act of trading goods (including whatever is representing money) is not negative in itself, osit.
Shinzenbi said:
Is there such a thing as “personal values substitution process” that happens when someone brings forth what he is not ? Will my values gradually and insidiously be replaced with antivalues ? Is there a risk that the more I do business, the less human I become ? For instance, by thinking daily of profit, money, happy swindling ;), prejudicing the competitors and being very proud of myself, so-called justified lies, voluntary omissions (the list is long)… is there any chance that one day I support evil ideas/people ? Example : Pierre Bergé who said that

“as workers rent their arms, women may well rent their bellies”

to carry babies for others, thus making maternity and children a business.
I would say it depends on the person in question. Maybe on man will succumb to the pressure and become deeply aligned with the negative chain of events while another may grow as a result of the internal conflict that occurs as he works for a living in a negative environment while striving to be of a positive orientation.
Such conflict may also propel him to do the least amount of damage possible while he is not able to figure out how to have a livelihood that is part of a positive chain of events.
For instance, perhaps it is not necessary to "happy swindle" or to be proud of prejudicing competitors?
Shinzenbi said:
If such a danger does exist, how can I protect myself of it ? I want to stay sane. What comes to my mind when i think about business and psychopathy is "give them a paradise, they'll turn it into a hell".
I empathize with your plight, Shinzenbi. I am not a business owner but as a former employee of a major financial institution I once said to my boss "this place is turning me into a monster". That realization was the catalyst, so to say, to consciously reject - internally - the modes of action that the company's corporate culture dictated while acting outwardly as I needed to do my job as best as I could. I also tried to make my immediate environment less negative by promoting trust and cooperation between my coworkers that seemed to be of a more positive nature.
This did not eliminate the tension of working there but it did free me from identifying with the psychopathic or otherwise disturbed characters I had to deal with daily. Being there, there was no way of not dipping my toes in the STS waters of modern day finance, but in the end I think it was a profitable experience because it taught me how to deal with some very difficult people and how to keep who I am separated from what I had to do.
I am wary of giving advice but if I may suggest, IMHO, I would begin by having a strong mental attitude of not letting your values be soiled by the business practices of your particular market. At the same time, maybe you can think of ways to change your particular circumstances as to diminish your involvement with the negative elements? It is probably not possible to avoid them all, but maybe you can find some comfort and inner freedom in knowing that you are doing the best possible given the circumstances?