Explaining Isn't Excusing
Though we often use them together, an explanation is not an excuse.
An explanation can be used when we give evidence for an excuse, but an excuse is about culpability, which is determined by a set of values, values that can exist outside of a set of facts. An explanation, in contrast, comes about by the application of a set of principles to a set of facts.
Here’s an example: after the airliners struck the World Trade Center on September 11, 2001, I was asked by someone, “Why do they hate us?” Having read some article or other about how the U.S. had armed fundamentalist Muslims fighting the Soviet army Afghanistan, I was stupid and piped up with an explanation: “they” were extremists we once supported, and we had betrayed them by pulling out after the Soviets left and, later, by stationing troops on what they considered holy ground during the first Gulf war. The result of my feeble attempt at an explanation was that I was accused of “making excuses for terrorists.”
Innocently, I thought I was applying a pretty simple principle to the facts at hand: when people feel betrayed, they get angry and sometimes lash out. I didn’t think I was passing judgment on the behavior, as that would have involved including in the equation a separate moral value.
As an old-fashioned peacenik, I don’t think anything excuses terrorism. As a rationalist, though, I do think there are explanations for why people engage in it.
So maybe equating the words “explanation” and “excuse” is a rhetorical strategy of rejecting the reasons of those with whom we disagree by impugning their ability to reason altogether, thus circumventing understanding with umbrage.