Personally, I'm a moral absolutist, which means that I believe there are absolute truths. That is to say, there exits truth which is indepedent of opinion. Plato differentiates them with the terms episteme (knowledge) and doxa (opinion).

I don't adapt my morals because I believe that if I have knowledge of what is moral and immoral that these themselves never change, and are not dependent on my whim or opinion.
However, I do feel at liberty to hold to a morality which is not entirely consistent with societal ethics, or as we shall say - the laws of our society.

Laws =/= Morals

For instance, we generally hold that lying is immoral.
But except under extrordinary circumstances, it is not illegal to lie.
Similary, the law of my society also permits abortion which I also consider to be immoral.

On the other hand, I could be commiting a criminal act by saying certain things in public, yet I do not consider it immoral for a person to hold a certain opinion or say something they believe in.

So I do not feel myself at liberty to change what I consider to be eternal principles, because I am not a moral relativist (which I feel must logically end up resulting in immorality). But I do feel at liberty to hold a moral code at odds with society's ethics & laws.

I think that the better question to ask is whether or not we should abstain from adopting the moral norms of our society and why. I'm personally not concerned with what society thinks about my choice of lifestyle, though I think most would find my lifestyle to be ethical in their opinion. I'm an atheist, but just because a moral norm has its origin in religion doesn't invalidate the utility of the moral norm, though I do reject the absolutism and asceticism of religious morality. I'm more concerned with the utility of the morals that I adopt than I am of their origins. We should hold to the fire the moral norms of our society, but we shouldn't reject them just because.

from the OP it seems you are concerned with morals being imposed on individuals by outside influences and the possibility that these influences cannot be avoided.

i agree that the opinions and morals of society, our own and others, will influence us, and sometimes it is difficult to separate that from what we would natural believe or accept had we not been conditioned. some people find it easier to disengage from these influences than others, some tend to believe by not following them they are not being influenced by them (a sort of blind rebellion). i personally have taken a long time to try and discover if there are indeed absolute moral values, and if so what are they. i dont have the answer to that question.

in the meantime, i think i am an absolute relativist...i believe there are absolute morals for each individual at any given time. in other words, you cant make a list because every decision has to be made individually, according to the conditions, the participants-but i dont consider it a relativistic point of view because i believe there is only one absolutely moral answer to every moral dilemma for any one person at any given time.

i think it is every bit as important to ask why society encourages us to go against our own inbuilt moral beliefs. it is very difficult to be a conscientious objector even in a non-threatening and non-judgmental way. it causes social confrontations and discord.

The ground rules of moral thinking are dictated to us by previous generations and we by individual or net observation modify our morals to fit the dilemmas life has the habit of producing. Our fathers would or could not imagine the ethical quandaries we have to face with the advance of science. There is an underlying moral view that we can all apply but the problem has always been dogma, the dogma that tries to convince us it is ethical, when in fact it is a morality that has long outlived its purpose.