I think it's increasing because things that are recent naturally progress from things that started in the past. The examples you cite are all post 1960s, which

I think it's increasing because things that are recent naturally progress from things that started in the past. The examples you cite are all post 1960s, which is when a lot of these movements began (political correctness, feminism, and so on). Once the slurs are banned, to use the PC example, the movement doesn't stop, but instead the focus moves onto the next thing so that now the debates are about how to label someone who suffers with mild myopia, or whatever today's campaign is.