I don’t know where other countries fall in voter turnout, but with somewhere around 40% of eligible US voters actually casting a vote (and that’s for presidential elections, other votes are much smaller), I don’t know that obsessed is the correct word. Bombarded might be better.
Most US citizens can’t name more than the Repub/Dem nominees and a long-shot 3rd party candidate. Too many don’t even seem to realize there are other parties vying for their vote. When you’re obsessed with something, you tend to go overboard learning about it. Frankly, most US voters tend to be happy when the whole mess is over, so they can hear about something else on the news.
Of course, the Dem/Repub pundits and supporters tend to be obsessed, and usually a bit too polarized. I like that, it’s a lot of fun annoying both sides. There were a lot of seriously depressed, nearly suicidal Dems after the 2004 elections, a lot of riled, angry Dems after the 2000 elections, and panicked Repubs when Clinton took and held office. So it does seem some folks are taking all this more personally than in the past, but frankly, they tend to be a little unbalanced to begin with. 
I tend to view it more like I view American Idol and similar shows. Some people don’t care, others care too much, and most realize how rigged it is but they’ll watch it with a certain degree of amusement. You don’t really get much option, election coverage tends to be 24/7, whether you like it or not. With only two parties given serious chances by the media, there’s no way it can avoid being polarizing, at least on a superficial level. You’re given a choice of A or B, a vote for C is a throw away vote, if there is even a C vote you happen to like. So A choosers are really worried about B getting elected and vice versa, while C choosers get “polarized” because they have to do crazy things to draw even a minute percentage of attention and votes.
Still, in the end, a solid majority of people, even those who vote and pick a party, aren’t polarized, the media is, and assuming the 80/20 rule, that 20 percent of folks who do care are venomously polarized. As such, they make the most noise and do the most stuff. A little like the “violence” in the US, to foreigners this all looks pretty crazy (especially to Canadians, their government seems to have an interest in making the US look scary and insane), while the reality is much more mundane. Mundane doesn’t work on TV, though.
Of course, some countries’ elections are far more polarized, just not though mass media outlets. You don’t typically see riots and gunfights after a US election, but that might be because they’re held in November. 
And personally, no partisan folks have shown up at the door yet this year, there’s only one sign in someone’s front yard for the 2 mile stretch of road I drive to the freeway, and nothing around the other places I go. Based on these details, this election is kind of looking like a bust so far, especially compared to 2004. Perhaps it’ll change in the coming weeks. Considering the choices, I’m not holding my breath.