I do agree with you, the envirment have a huge influence in how a person is going to behave and to what is that person going to react.
I would said that I don´t agree with you on the parts of the choice. Sometime is not even the person choice, what would happened if you are 4 or 5 years old and you play with your friend games that are not normal. That child will grow with that image and you know that our psycological part of the child will play a big part in his/her life. So, I would said that it is not always people choice. I am not sure if i explain my self well.