Josh Marshall discusses here the different reactions to Pres. Obama's calm regarding the recent terrorism attempt. Some, such as the cited TPM letter writer, view this calm with relief that a grown-up is now in charge. Others, particularly Republicans (who all apparently now think exactly the same thing about everything - so much for freedom-loving), view Pres. Obama's calm as an outrageously insufficient response to the war on terror. Many of the latter dramatize the event to try recreate the climate of fear that the Bush administration sought to maintain.
There's a simple point to make here about terrorism:
The primary objective of terrorists is not killing in itself. Terrorists most basically seek to generate terror and instill a climate of fear in a population as instruments for achieving political and/or religious goals. They succeed most efficiently when we help them do their job by allowing ourselves to be terrorized.