Describing a joke out of context can make a person sound very cruel indeed. I've been in situations where someone has made a joke about me dying, for example, and I found it to be funny and light-hearted. But if you strip out the context and say "he made a joke about me being murdered", it sounds far, far more cruel than it really was.

The reason the blog post was written is that jokes that would usually be fine among friends can take on a different tune as soon as the power dynamic changes, and that's not always obvious to the person with the upper hand.