Venezuelans have spent years trying to persuade the world about the brutality of dictator Nicolás Maduro. They probably never expected Mr. Maduro to help them make the case.

On Monday Mr. Maduro promised to use Venezuela’s military to block international humanitarian aid for his own people. “We are not beggars. You want to come humiliate Venezuela and I will not let our people be humiliated,” he said on state TV.

But...