Political vitriol is a bipartisan phenomenon. So is the inclination to use current events to score points against ideological opponents and to advance agendas.
High profile shooting sprees by white people are tailor made for the lefts agenda. They allow the left to point the finger at the root causes of crime. Those root causes are always an insufficient amount of liberalism and or an abundance of conservatism, to paraphrase a recent George Will commentary. Conservatism therefor is implicated as an accomplice to the crime. The answer is to silence dissent (ie Fox, talk radio etc...) or otherwise attempt to restrict speech of political opponents. It also provides the opportunity to discuss anew the lefts desire to disarm the citizenry.
The recent Arizona tragedy presents fewer opportunities for conservatives to exploit. It would be hard to use it as an argument for lower taxes for example. But it could be used as an argument for tougher sentencing or for more jails. The right has not done this, however. The reason is that it doesn't fit this particular crime insofar as the perpetrator wasn't free on a technicality or because of insufficient jail space. I would also like to think that basic human decency is a factor as well. So the right is scoring political points mainly by challenging the despicable attempts by the left to pin this crime on, well, basically conservatism.
I am glad to be on the right on this issue and I would be embarrassed to be a liberal right about now.