> In the past few years we've had politicians on both sides killed in politically motivated attacks. I think that's a worse tally than the US as well. (emphasis added)
A cursory glance at the various Wikipedia lists of politicians assassinated in either country rebuts your last point.
US political discourse is vastly more hostile than you give it credit for, as well. Veiled death threats (shooting pictures of opponents, burning in effigy, etc.) are increasingly common, particularly on the conservative side.