While George Washington's business model very much did take advantage of people, it would be more accurate to say that he, like many other white men, benefitted from a system of legal and institutional inequalities that allowed him to exploit less-privileged groups.
One example of both a legal and social advantage that increased Washington's personal wealth was his marriage to Martha Custis. She was a wealthy widow who owned hundreds of slaves and a great deal of land. The legal system at the time, borrowing from English law, deemed that upon marriage, a man owned and controlled all of his wife's financial assets under the theory that the couple was "one flesh" and the man the "head" of this one body. Martha, as a wealthy woman, could have demanded a marriage contract that would have protected some of her assets and kept them under her control. She did not, as social custom also benefitted Washington: Martha had been socialized to believe in male superiority and to think it natural that her husband should control her assets.
The most glaring example of legal and institutional exploitation, however, was Washington's use of slaves. He was a wealthy landowner in his own right before marrying Martha, with a fortune based in agriculture. What made agriculture so profitable for him was the right to own slaves. Because slaves did not have to be paid any salary, could not quit or refuse to work, and could be kept in poor conditions, most of the proceeds of the sale of crops fell into Washington's hands. This was highly unfair, as the people doing the hard labor that enriched Washington got next to nothing, but the law was on his side.