Much of the change is due to definitions:
Discrimination once meant making an informed choice.
They are defined by a society and its leaders to be:
What you can get away with while living in your society. Look at the "moral" actions of the countries that brought "enlightened rule" to the "heathens" where there were things to plunder. Totally "moral!" Each generation looks to what its parents got away with and does them one or two better.

Ethics, are another story. They are the building blocks of a complete person and thus a successful society. Problem, there are few actually teaching ethics...anywhere.
JMO
~Richard