I'm happy to hear your well-organized opinion. Very, very nicely put, but, if you don't mind, let me tell you one thing (regarding cultural determinism) for more balanced view on this matter.
Yes, some cultural determinists argue that the culture in which we are raised determines who we are at both emotional and behavioral levels. Extreme cultural determinists would go further, arguing that even physical traits (e.g., height, body weight or facial appearance) can also be affected by culture. On the other extreme of the view are genetic determinsts, who argue that our genes determine who we are at every level, including physical, emotional, and behavioral. The controversy between the two is nothing but the so-called 'Nature vs. Nuture (or Gene vs. Environment)' controversy. (I don't want to articulate further on this matter, because that's not my point.)
All determinisms including the above two are basically correct in a sense that there are cause-and-effect relationships in every process we perceive. But determinism is quite easily and too often misunderstood. Some people might even say, "If actions of a man are (pre-)determined, how can he be held responsible for his actions? On what basis can we punish him for his 'unavoidable' actions??" (More relevant example here can be, "If Bush's war on Iraq (or some Americans' support for war) is (pre-)determined and cannot be avoided, who can blame him (or them) for this matter?")
They are misunderstood, however, for what determinism tells us is not that kind of (pre-)determination. When rightly understood, what determinism (or scientific approach) tells us is merely that, if there is an event, we can trace back to the cause. That's it, and nothing more. Determinism does not foretell that there'll be only one single path we should follow. That's something. Yes, we cannot be free from causation, but, almost in every case, we have some alternatives that we have freedom to choose. Due to this freedom (or free will), we are responsible for our actions.
As you noted, we may have different thoughts because we live in different environments. But this does not exclude the possibility that we human beings in the world altogether can aim at a single target: More Peaceful World!! That's because, right now, we have various options on our hands, and also because we have moral consciousness to tell good things from wrong ones.