This is a rant that I've had for so long, and it's so hard to concisely summarize. This does a great job of explaining in detail, but it is much harder to tell your boss to read a long blog post when you disagree with him about the correct approach. I found a metaphorical approach to sometimes be helpful. I use this:

On a dark night, a blind man jaywalked and was nearly hit by a drunk driver who swerved and killed a pedestrian wearing black on the sidewalk. What was the root cause? Was it because the man was jaywalking? What if he was jaywalking because he was blind and didn't know any better? If the driver wasn't drunk, could he have braked instead of swerving? If the pedestrian was wearing brighter colors, could the driver have swerved a different direction? Sometimes there is no singular root cause, but rather a complex interaction of multiple failures that may or may not arise if you take one failure away. There may be a better approach than to use a tool that is designed to hone in on a singular root cause.

Unfortunately, this only sometimes works. The rest of the time, they actually do try to pick apart the example and claim there is a root cause. The only recourse then is to present an alternative singular root-cause and say that by trying to force a single root cause interpretation instead of accepting the complexity of reality, that your root cause will ultimately reflect your own biases rather than reality (for example, who do you hate more: jaywalkers, drunk drivers, or pedestrians that wear black at night?).

I still wish I had a better way of explaining this succinctly, in a way that makes it more clear.