First and foremost, I know trying to have a meaningful dialogue in this section is about as smart as farting into a fan in the summertime, so I'll be brief. I don't believe your sumo picture and samurai videos make your point that they're both just stupid costumes.
Both the sumo and samurai are grade A bad mother fuckers in Japanese society. They are powerful, and respected. When someone puts on a sumo or samurai costume it doesn't denigrate all Japanese people. Nobody treated John Belushi or Richard Pryor like shit, they had swords.
When someone paints their face black like in that vile Trayvon costume, given the history of blackface and its portrayal of blacks
it seems worse.
That's just my two cents. As a black guy, I'd prefer if all racists slathered their faces in grease paint and said nigger as often as they liked. It makes for easier identification. Maybe if I were Japanese I'd be mad as fuck right now about your videos but at least they're from 40 years ago. Trayvon is a little newer and still stings for a lot of us.