I disagree. I don't see why doing that which shouldn't be done at all inefficiently wouldn't be even more useless.

I'm not sure of the exact context, but Drucker is primarily a writer on management and business. He wrote a really high number of books outlining management principles, he's considered one of the fathers of the discipline of management.

So to his audience, he's saying "Don't get excited how efficient your card-puncher-tallying system is, when your real goal is high quality output." I think he's reminding people to not get caught up in doing a process well if the process doesn't produce real results.