It might be even easier to see & understand this phenomenon by looking at the history of rights for women and black people. These also took generational turnover, and attitudes among the older generations changed more slowly, and we’re still not even done yet. I can see this right now pretty clearly between my adult family/friends and our children, where the adults are still getting used to and learning how to talk about gay rights, are squeamish and sharing cringy talking points about transgender rights, meanwhile the kids are all fully on-board with equal rights for all and just have no problems with non-binary gender or sexuality. It’s funny after multiple rounds of this happening over multiple centuries that we still have trouble actually standing by our motto of liberty and justice for all.

These are, yes, examples of cultural belief changing slowly and happening less because people changed their minds and more because younger people came to a new conclusion. I’m curious what you meant about it maybe being a counter-example, what did you mean there?