Some years ago, I was convinced that my neighbor was a drug dealer, because I saw dealers going in and out of her apartment all day long. I was wrong: she would never deal because she was a very Christian person, but she sheltered the dealers. It was a totally new concept to me. Why did she do it? Because, she said, they were kids with no hope of getting a job. These dealers were hard to eradicate: they had been on our street for decades, but when that neighbor moved away, the dealers on the corner of my street moved too. It convinced me that dealing is the kind of crime that most often comes with a support group.
It reminded me of another Christian I had met in Ireland. He would never commit an act of terrorism, but he would always hide a terrorist. The idea of calling the police seemed to him equivalent to a betrayal.
Similarly, I knew of a very pacifist Palestinian who would never commit an act of terrorism himself, but he understood and would have protected terrorists. Why? He understood what they were fighting for, agreed with the ends if not with the means. And of course he was constantly subjected to propaganda. For instance he told me that the proof that "the Jews own America" is that the star of David is on the US dollar; I guess he meant the 13 stars from the 13 first states.
I do not understand tacit consent: to me, it is like shooting yourself in the foot; but it is a force that we ignore too often.