PC is the perception of a group of people by another group of people, the first group don't want to offend the second group so attempt to ensure that nothing can be said about the second group at all, by anyone, unless it is positive.
This then includes everything no matter how inaccurate, ridiculous or stupid such a view or course of action may be.
People in the second group may not actualy mind certain things, like the parents of young children letting them climb trees, full aware that the child may fall. These people are referred to by the PC as "delusional"