(Note: scroll down for update)
In fact, Democrats have raised money off of tragedies before, such as the 2013 shooting at Sandy Hook Elementary School in Newtown, Conn., in which 20 children were murdered.
In June 2013, the Democratic Congressional Campaign Committee (DCCC) posted a blog entry demanding a vote on new 2nd amendment restrictions in response to the tragedy, alongside a giant red "CONTRIBUTE NOW" button.
The post invited people to sign a petition to urge House Speaker John Boehner (R., Ohio) to hold a vote on gun-control legislation. Those who signed the petition were urged to "take the next step" by opening their checkbooks.
But… but… but…
UPDATE: Some liberals are hazzing a sad on Twitter, and complaining that something something conservatives LIE. Here are some more examples of Democrats fundraising off of the Newtown shooting, which occurred on December 14, 2012.
Obama campaign email, Jan. 17, 2013 (links to donation page)
Joe Biden email, Jan. 25, 2013
DCCC email, Feb. 13, 2013 (links to donation page)
OFA email, April 11, 2013
OFA email, May 6, 2013
OFA email, June 11, 2013
DCCC email, June 14, 2014 (links to donation page)
Elizabeth Warren campaign email, Sept. 14, 2013