I think George Takei is one of the coolest human beings on the planet. But I must admit to a bit of crunkling of the nose at his "Today we are all Japanese" tweet. Uhhmmm...no, I'm not Japanese. I can sympathize with their plight, but I cannot BE one of them.
It rather makes me itch in funny places for me to assume that I am Japanese, even in spirit. It tastes just a bit of racial/cultural appropriation.
[EDIT: Various responses have helped me drill down what's bugging me about it. It's the auto-RT of his message. Without doing anything else. As if just RTing will be enough to support the people of Japan. Just RTing by itself does little to help those in need.
Not unlike an earlier discussion here about the RTing or facebook posting of political memes as if that actually does anything by itself to help the situation.
Thanks to commenters for helping me refine this!]
[EDIT TAKE TWO:
entelodont had a valid point. I should have apologized for the initial statement when I realized it was not cultural appropriation that was bothering me, but the auto-memeing of something that doesn't really help the situation by itself. The initial statement was exceedingly insensitive. What I meant to get at was that repeating a "We are all PoC" meme when you are not a PoC is where it starts to read like cultural appropriation. Not that Takei was doing so. Mea culpa. ]