Really? Suppose you went to a website for a similar kind of company but with a prominent Wild West theme, sheriff stars for buttons and products called Lasso and Six-Shooter. If I had to guess, I'd say that company was anything but American. Heroku's website oozes fanboy kitsch in much the same way. The difference is that a lot more technologists are Japanophiles than wannabe cowboys, so we don't notice as much and just lap that shit up.
On that note, I remember going to Black Angus Steakhouse when the first restaurant in Korea opened at Gangnam-yeok, Seoul. The greeters at the door wore cowboy-style outfits with handkerchiefs around their necks and enormous hats that almost swallowed them up. As customers entered, they would sing out an awkwardly pronounced "Howdy, partner!" in unison. Then, rather incongruously, they would bow in the customary Korean fashion.
Now, I haven't ever been to a Black Angus in the US, but I'm guessing they don't ham it up there nearly as much. :)