Keith Thompson's article that you really must read in its entirety,
Excerpt:
A turning point came at a dinner party on the day Ronald Reagan famously described the Soviet Union as the pre-eminent source of evil in the modern world. The general tenor of the evening was that Reagan's use of the word "evil" had moved the world closer to annihilation. There was a palpable sense that we might not make it to dessert.
When I casually offered that the surviving relatives of the more than 20 million people murdered on orders of Joseph Stalin might not find "evil'" too strong a word, the room took on a collective bemused smile of the sort you might expect if someone had casually mentioned taking up child molestation for sport.
My progressive companions had a point. It was rude to bring a word like "gulag" to the dinner table.