> Having worked at a U.S. military base in Japan, Snowden reportedly had a deep interest in Japanese popular culture and studied the Japanese language.[15] He also has a basic understanding of Mandarin, was deeply interested in martial arts, and claimed Buddhism as his religion.[16] Before his disclosure of top secret documents to the public in 2013, Snowden had travelled to Hong Kong for a holiday with his girlfriend Lindsay Mills.[17]
He speaks some Mandarin (which would be somewhat useful in HK, especially if he can read it, which he probably can since he's studied Japanese), and he's been to Hong Kong before. All his justifications about HK's legal system is probably relative to the other choices he was considering (presumably Japan, HK, Taiwan, mainland China).
He worked in a start-up which sold anime. "Anime nerd flees US, resurfaces in East Asia" is not really surprising. I guess he picked HK because it has a lower US presence than Taiwan and Japan; and mainland China was a bit too scary.
He could have picked a more secure place to flee to, but most of what he's done hasn't been totally rational.