Boseman said it was important to "acknowledge the heroes we have in real life."
"The details of the case are quite frankly heartbreaking, disturbing, disgusting and infuriating all at the same time."
The North Korean leader's trip comes as ties between Beijing and Washington are being tested by a major trade dispute.
The ISIS-linked sect has been involved in around 30,000 killings over the past decade.
"I need to have that weapon on me at all times in case something would happen," an Ohio teacher said. "I know the other teachers feel the same way."