“Leaving Neverland,” which has prompted the Michael Jackson estate to file a $100 million lawsuit against HBO, is an appalling story of predatory child sexual abuse, told in such painful detail and at such heroic length (four hours over Sunday and Monday nights) that it’s impossible to dismiss. But what the series also makes clear, beyond almost everything else, is the power of willful blindness.

Producer-director Dan Reed builds his entire project around interviews with two subjects, Wade Robson and James Safechuck, who...