The very wonderful Colleen Graffy may have been correct that the Guantanamera suicides were 'good PR' (I bet the Independent's editor had to change his pants when he heard the news) but I'd suggest that it's not a sensible thing to say if you're "Deputy Assistant Secretary of State for Public Diplomacy".
As for 'asymmetric warfare', if Palestinian suicide bombings can be justified theologically (to a Muslim) as an act of war, there's no obvious reason why suicide designed to embarrass the US shouldn't also be justified. Suicide as 'warfare by other means' is something Brits should know about. The slow suicide of the IRA hunger strikes were part of Sinn Fein/IRAs war against Britain.
Not that we can talk about suicide bombers. Didn't Churchill propose "You can always take one with you" as a slogan in case of a German invasion ? I suppose the difference is that we'd have been topping troops. The heroes of Nablus and Ramallah seem to prefer buses and market stalls.