1. Japan has the world's oldest population, which means there's a pretty high level of unfamiliarity with and suspicion of many modern technologies. Fax machines remain more popular than email, for example.
2. Video games are a much larger and more mainstream part of Japanese culture than they are in America, and consequently they're seen as "serious business" to a much greater degree than they are here. It could be that hacking a game in order to cheat is viewed similarly to how we'd view cheating at gambling or professional sports. (Especially if the game is played competitively, and/or the cheat is intended to get around in-app purchases).
3. Very, very strong cultural emphasis on honesty and following the rules. Japan is consistently, by a wide margin, the world's most honest and law-abiding country, and those who aren't are viewed quite harshly. Like all things, this can be taken to extremes.
Based on the experience of female friends: don't believe everything you hear about Japan. If you are a gaijin being mugged or harrassed by Japanese men, even police will question your word when describing the villain. They will honestly ask if you have "not just seen him wrong, because Japanese people don't do such things. Must have been a foreigner."
Also, witnesses reject to help, look away and mind their own business. Sometimes not even moving away on a train, just sitting there while a woman gets harrassed, mugged or raped. These women do not always report such crimes due to the shame of something like this happening to them, and other people not even helping. The logic goes so that they themselves must have deserved it, since noone came to their aid. For more, see schoolgirl gangs beating and raping single bullied targets in public places like restaurants. People just sit and look away. Some take videos and pictures to post online.
In court, the judges do not question the legitimacy of police findings and accusations, so if the police presents evidence that would accuse of you wrongly but which is half-assed or plain wrong, judges take those evidences at face value. The onus is on you to prove thee two biased parties wrong.
Don't believe Japanese stereotypes without a couple years spent in a big city there.
This is a huge overstatement. Fax use is still common, but in no way is it more "popular" than email.