Yea - this is always a tough one. And it manifests itself in a number of areas for different people, whether it's professional life, family etc.
I think it's a very personal thing for each individual. It basically comes down to a choice of whether we feel that the 'cause' - whatever it may be, and living a life of honesty in all regards is worth the penalty we feel we may have to pay by doing that. And as you said, society and people being what they are, there will very likely BE a penalty.
For me - I try to approach such decisions from a 'where will the greater good come from via my decision ?'. Where will the harm be ?
And we have to be willing to live with the repercussions of that decision. Some of us are a little more pain resistant. Some of us have more to lose - i.e. the ramifications could be more widespread.
But one other thing I always weigh into these internal discussions & debates is where ego is sitting in all this. It seems when we want to stand up for our beliefs in spite of all logic appealing to us to do otherwise that it's often our ego that's screaming loudly. It screams we're being a hypocrite. It screams we're not 'true' to ourselves. Etc Etc It wants us to believe we're less than we think we are.
My response is usually - 'Yea - I hear you - but this isn't all about you' ! There's other factors to be considered here which MAY mean you (ego) have to take a little wound so that someone else isn't more fatally wounded. A sharing of the damage society passes out to us.
Never an easy choice.
In my history I have chosen in both ways depending on the overall picture. And still do. I'm willing to take a harder hit as long as I feel it's only me that's going to take the brunt of it.
But this is drifting into generalization...........
When it comes to poly, I really feel our love & sex lives are nobody's business. I don't feel attached to it as some 'cause' I need to champion even though I feel it's a better and more reasonable way to live. If I were approached by anyone who I felt had a sincere desire to explore it, I would be frank with them. Otherwise it's a private matter.
Good luck with your choices. I hope you find that balance too.