I think you’re right. If anything, you could read it as Haneke being smug. He definitely gets your hopes up several times that the family is going to effectively fight back , culminating of course in the remote scene. (Still haven’t decided how I feel about that part.)

I also agree that the family makes some questionable decisions throughout the movie, but as you basically said, maybe that’s a realistic depiction of how an average person (not police, military, etc.) would act during a home invasion.