Awesome topic, very relevant to me at the moment.

I think you make very important points. Life and your vision of life is defined by your perspective. Your perspective that is both impermanent (subject to change) and heavily influenced by what's around you.

That is to say that anyone can do good believing it's good, when it's actually bad...Ofcourse what defines "good" and "bad" isn't as black and white as people might like to think so.

Essentially, I think it's all subjective. All you can do is use your human empathy to act in such a way that you believe will minimize negative impacts (Anything that causes harm to an individual or group whom recognize it as harmful), and maximize the positive effect of your actions (Anything that generates experience without causing suffering).

In Buddhism, karma is determined not by the action itself, but by the intention of that action.

The truth has no name and is, in my opinion utterly subjective. The law especially, which varies dramatically is a prime example of a government imposing what it believes as right and wrong, true and false.