Here’s how I see it.
First, because some folks have been the culturally dominant force for quite some time, they spoke and acted as if they were the only cultural force. All others, if they were somehow noticed, were referred to with belittling language, and since they weren’t dominant, they could do very little about it. It kept them “in their place.”
Slowly, demographics changed. Attitudes adjusted. The dominant culture, while still being the largest, has had to cope with the up-and-coming minority groups gaining political, economic, and social power. The dominant group seems to have split into two factions over how to cope with this, as defined by their strategy:
The first faction has decided to play nice with the newly empowered minority groups. Instead of using the older, perhaps insensitive language to refer to minority groups, they began to embrace a more inclusive language, designed to be less offensive, perhaps even what the minorities wish to be called, or at least taking into account that differences don’t make someone necessarily less-than.
The second faction, unwilling to recognize (out of habit? fear? denial? jealousy? insecurity?) that the minority groups are slowly but unstoppably gaining ground, laughs at the first bunch, and mocks inclusive language as “Politically Correct.” Perhaps they believe that if they just keep up with the mockery, their cultural hegemony will remain intact. Good luck, I say.
I will say that both factions often go too far in their polarized directions, since that’s what binary systems tend to do to people. On one hand, the first bunch sometimes goes to ridiculous lengths to avoid offense, coming out sounding just silly. However, the second bunch could gain a lot by, instead of mocking, learning from the first. Hopefully, from my point of view, the two factions of the culturally dominant group will somehow average out someday, and once again, we’ll all just be people.