Politicians and public figures are fundamentally like all other human beings and have the same basic responses to tragedy. This is true no matter their position on controversial issues of policy (say, gun control). So it is no surprise that they respond immediately, like the rest of us do, with familiar words and phrases that express their human solidarity with those who suffer. Even the most accomplished speechwriters will take hours or days to come up with words adequate to great suffering. No human being, even the most articulate, can offer adequate words in the first moments after terrible news. To demonstrate that level of rhetorical fluency would in fact be to demonstrate an inhuman lack of empathy. Inarticulacy is the proper, empathic immediate response to tragedy.
Excellent musing on the responses (and counter-responses) to the San Bernardino shooting.
Andy Crouch, “On ‘Thoughts and Prayers’ After the San Bernardino Shooting: Prayer—and lament—is the proper first response to tragedy.” Christianity Today (December 3, 2015) (link).