We are always trapped by outmoded and irrelevant ideas. It's difficult to cast aside those old ideas we grew up with, the ideas about who our friends are and what is important. To do so causes us to worry. We may feel that we are "letting our side down" and that there might be some retribution from our own people because we have "changed sides".
Powerful interests and old loyalties restrict the flow of information on topics like this. If you face a personal crisis of belief, all the authorities you trust are likely to reinforce your old ideals.
One needs a strong imagination and a strong focus on truth, to purge an old "less true" but well known story from your mind and to replace it with a better "more relevant" story. There is a time when both stories compete for "top dog" status in your long term memory. You are likely to go through a period of uncertainty when you are unsure of yourself; when decision making is difficult.
People create ingenious ways to protect their existing belief system, whatever that is. There is no external evidence that is ever convincing to the individual. If there is to be change of any kind it has to be an internal job. Public polls and scientific evidence are never enough to change any person's mind. People can only Adapt to Experience, when they are willing to see the evidence of their own lives, and when they back that change in outlook with their own evidence.