As you said, it's hard to compare because of methodology and such. Yes, the US looks bad when you average everything together, but that ignores that some places are very different from others. Basically, if you stay out of blighted urban districts ("ghettos"), you're far less likely to suffer from violent crime. Many of the homicides here are because of gang violence, something that really only affects gang members and people living around them.
If you take out areas with high crime in any country then of course the statistics look better.
Similarly of course it's possible to find areas in one country that are safer than areas in another country if you want to.
You're ignoring the fact that there's a huge racial division in the US. If you're a white person, gang warfare in the black or hispanic ghettos simply does not present a danger to you the way it does to those minorities. (Note I'm not saying these problems shouldn't be dealt with or that these minorities should be ignored or that the deserve it, just that this is the reality on the ground.)
From what I can tell, in European countries the divide isn't so stark and middle-class-and-up people are more likely to be victims of petty and street crime like muggings. Here, if you're a white suburban dweller, you just don't have to worry about being victimized in a mugging or carjacking very much, while in the ghettos you definitely do.
