Do you know which JP server was it that had ad spam? I've been in a JP server since beta. For about 2 months after launch we had crazy ad spams here, then they just died off completely. My last ad tell was about half a year ago, and only that one single tell.
As for your last question, yes there is definitely a cultural difference. Have you been to Japan before? Anyone that has been can tell you that they act differently from Westerners. The first thing you will notice is that they are very polite. Working with them, you will find that many of them seem to expect hard work before benefits, and they have a sense of honor and duty, but remains very humble. This is very different from the West where many wants instant gratification, and have very high self-entitlement ideas. There is definitely a very wide cultural difference.