I’m actually really glad that the new episode tackled racism and prejudice like it did, showing that even those considered paragons, and those who have been burdened with strife, are not above looking down on another because of their race.  That it was told in the Crystal Empire makes it even more poignant.

Chrysalis kidnaps Cadence and seeks to invade Canterlot=All changelings are evil and not to be trusted.

Sombra enslaves all of the Crystal Empire, banishes it from existence for a thousand years, and brainwashes and corrupts hundreds of Crystal Ponies leaving them with PTSD=Not all unicorns.