Two people are in an argument. One person, upon noticing their point has been refuted, says something like "I was just playing devil's advocate" or "I was just trolling."
A person says something insulting, and attempts to pad it by going "Haha, I'm just joking."
- Bobby makes a mistake, and, upon being called out, justifies it by pointing out someone else's actions—and claiming they were the cause of Bobby's actions, which lead to the mistake
All of these things share something in common, and I want to refer to them in a similar way. It has something to do, maybe, with avoiding responsibility? I want to say "cowardly," but that's far too strong of a phrase.
If I wanted to say...
Arguing your point, and then saying "Haha, just kidding. I'm just playing devil's advocate" is a bit... [word]
What could [word] be?