The reason the US is commonly brought into this is because of misunderstanding of the circumstances and general suspicion.
First off, sexual assault and rape laws are very different in Sweden, and the crimes he has allegedly committed wouldn't be translated as assault or rape in most countries. Though that doesn't necessarily mean he didn't do something bad to someone that requires legal recourse; what currently stands are accusations of crime under Sweden's legal code.
More importantly, suspicion arises because the Swedish prosecutor's office initially withdrew the rape charge and warrant for Assange's arrest, and weeks later the charge was brought back. Some time after that, a European arrest warrant was issued. Some are suspicious that this was due to pressure from the US government, as they would like to see Assange in prison, but I'm not going to give my opinion.
Also, Assange has yet to be charged. I'm not sure how this works in Sweden, but it seems in this case that they don't want to charge Assange until after a second round of questioning. That is what the extradition is for.
First off, sexual assault and rape laws are very different in Sweden, and the crimes he has allegedly committed wouldn't be translated as assault or rape in most countries. Though that doesn't necessarily mean he didn't do something bad to someone that requires legal recourse; what currently stands are accusations of crime under Sweden's legal code.
More importantly, suspicion arises because the Swedish prosecutor's office initially withdrew the rape charge and warrant for Assange's arrest, and weeks later the charge was brought back. Some time after that, a European arrest warrant was issued. Some are suspicious that this was due to pressure from the US government, as they would like to see Assange in prison, but I'm not going to give my opinion.
Also, Assange has yet to be charged. I'm not sure how this works in Sweden, but it seems in this case that they don't want to charge Assange until after a second round of questioning. That is what the extradition is for.