These videos explain the psychology of why the people who were against changing the definition of marriage suddenly changed their minds in unison with the group.
What would be more interesting is to note the people who resist the group pressure and maintain their own point of view. We all want to fit in, and we are taught from a very early age to conform, to sit in neat rows, to raise our hands in unison, wait our turn with the group, and on and on.
But the person who does not go along with the group, even when the group will turn against him, taunt him with derogatory terms, ridicule him, accuse him of hatred and dishonesty and of being of despicable character, and any manner of things, is the one who needs explaining.
Christ serves as the example of the man who stands alone for many Christians who have resisted the overwhelming pressure of the mass society to conform on this issue.
It is not that Christians are any more immune to group pressures and group dynamics than anyone else, or have stronger will, but to the extent that they have sound understandings of the teaching of their Church, they understand that they never stand alone, because Christ is always standing right there along with them, when they are doing the right thing.
It was really a radical and revolutionary teaching, for Christ to show us how to stand up for what is right, in spite of the overwhelming pressure of the group, including being spat at, mocked, ridiculed, and in his case at least, much, much, much more.