It's a different kind of racism there, but I don't think it's any better than it is in the US. Marrying someone of a different race is virtually unthinkable to most people in Japan, whereas marrying someone of a different race is pretty common in the US.
The year I lived in Japan, I can honestly only think of a few times where I felt any sort of racism against me, the extent of which was prolonged stares or people refusing to sit next to me on the train. I knew people would talk shit or whatever, but nothing really beyond that. Never directly denied service or outwardly treated differently. Maybe things have changed since I left tho...
As for the marriage thing, I'm not sure you can make that broad of a generalization. My close friend who still lives there is marrying a Japanese girl. Her parents were upset at first, but they got over it. I'd agree it's way less common than the states, but I wouldn't deem it unthinkable by any stretch.
And it's true, I really do not like the right-wingers, driving around in their big black buses, broadcasting their scary propaganda at deafening levels, with their Yakuza drivers, going around intimidating everyone all day long.
ya that stuff was surreal, people there totally tolerate it