I think you pretty much answered your own question...
The Japanese play with style, finesse, and originality. They tend to use a bigger variety of Pokemon, so Japanese players are generally harder to predict. They actually understand the concept that Pokemon is a game, not a lifestyle, and have FUN with it. This is why I respect the Japanese.
The Americans play with brute strength. "Competitive" players (aka The Nerdy Pokemon Chess Club) use a set tier list that they follow inch for inch when making their teams, and build their teams attempting to "counter" everything instead of just choosing some damn Pokemon and executing a certain strategy with them (too hard to most of them, apparently). They take the game too seriously. Because of this, 90% of American competitive battling teams look nearly identical. (Garchomp, Rhyperior, Blissey, blah blah blah standard fare.) Americans = sheep. Not only in Pokemon, but in everything that we do - we are sheep.
The good thing about this, though, is that the American standard teams don't know how to handle anything outside of the standards, which leaves them open to a lot of things. I've shut down whole teams of OU's in 3 vs. 3 with my Sunny Day Vileplume/Ninetales combo and Rain Dance Lumineon/Ludicolo combo which I find HILARIOUS.
The younger kids (from either country) tend use Pokemon with gigantic stats (aka Ubers) to make up for their general ineptitude at the game.
There are exceptions to all of these, obviously. There are quite a few Japanese that play the American style of OU competitive also, and there are Americans that play to have fun and be original. The latter are an extreme minority, though.
That pretty much sums it up.