Miki Dezaki, who first arrived in Japan on a teacher exchange program in 2007, wanted to learn about the nation that his parents had once called home. He taught English, explored the country and affectionately chronicled his cross-cultural adventures on social media, most recently on YouTube, where he gained a small following for videos like “Hitchhiking Okinawa” and the truly cringe-worthy “What Americans think of Japan.” One of them, on the experience of being gay in Japan, attracted 75,000 views and dozens of thoughtful comments.