One of my college English teachers pointed out that most people do not want to open their minds, but simply to have confirmation of what they already believe. My daughter's in-laws, who are actually very nice, tolerant people in most ways, are very religious and anty-gay. Now they have a gay grandson. I don't know if their relationship with him has changed, but they must be struggling with it.
We all know people who refuse to accept reality. I have reminded my sister many times that being gay does no harm to anyone and there's no need for her to be concerned about it.
On the TV show Northern Exposure some years ago, a character made a statement that it is heterosexuals who are "riding down life's highway at a high rate of speed without a helmet."