Since I’m one of the few non biased people here.
Historically : right wingers / republicans
Very recently : left wingers / democrats
dude everyone is biased in his opinion. People claiming to have no biases tend to be more biased than everyone else. It is simuilar to knowledge. Danning-Kruger-effect clearly proved that. If you understand what a bias is, you will agree that everyone has one and you never can be non biased.
even recent data of the US and the EU shows that your claim is for both regions wrong.
and also most of the violance is done by people who are to extreme for being part in a political party.