Can you expand on this? Are you suggesting that most of the people who say these things publicly don't actually believe them but are instead just trying to fit in to a certain social group?
Of course, it's one of the earliest results in psychology that social conformity has an influence on people's beliefs, even on readily accessible questions like whether line A is longer or shorter than line B. To me, if somebody professes a belief, acts on that belief, and works to convince others of that belief, then they effectively hold that belief.