Lots of people have defined it as torture
You have just not been paying attention. The latest was Sen. Chris Dodd just tonight as he spoke on the amendment to strike telecom immunity from FISA.
He went over the list of evil things the Bush administration has done (they are many) and one of them was water boarding. He read testimony from someone who had been water boarded and - Yes its torture.
To think otherwise puts you in the company of our latest simpleminded attn. general.