I'm not sure I'd call toning down the rhetoric a "political goal."
When it is only directed at one side of the aisle, of course it is.
8 years of Bush. Nobody said **** about the level of discourse. This is political. It's demonizing Fox News, talk radio, and Sarah Palin. That's the goal. Read the Daily Kos. The level of discourse on that site is the bottom of the barrel, they even "targeted" congressman Giffords for voting against Pelosi, yet blaming the level of right wing rhetoric is one of their chief talking points. It's one of the chief talking points on MSNBC for the past few days. Given the personalities on that network espousing those views, I am skeptical about their sincerity on the subject of rational discourse.
However. Even if the goal is pure, and people want to see a nicer political tone, why make that point on the back of this event when there is no evidence of any connection whatsoever between the two?