Correction, some people don't want to get it. It isn't that they don't get it, they do. They just don't want things to change, particularly if they find the change alien or threatening to them personally. They want all the people that are different from them to either pretend to be something they aren't, or perhaps even more convenient...be silent.
It is a theme that keeps repeating itself in human history, and yet people keep doing it...and then 30 or 40 years later when modern culture looks back and can't believe how bad it was...they pretend like they weren't part of the problem.