The problem may not be with what one says but how he/she frames it so that other people are in a receptive state of mind to listen to it.
You see, my family is the "I think that way and people who don't agree are morons" kind of people. This doesn't work ! If you start bashing people, how can you think they will be receptive to what you have to tell them ?
Thus, a minority should all the more wary about how it shapes what it has to say !
I don't think you can change someone's way of thinking with one big stroke. I do think, though, that you can bent people's thinking like a painter, by putting small color touches here and there, when you get an opening. Not a total change of perspective, but a little switching of the angle from which an issue is viewed, a little mind broadening.
It's not a matter of hiding thoughts, more a matter of thinking : "I believe this way. Now, how can I say it so that people will listen to what I have to say ?"
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The world is my oyster !