If waterboarding lead to the intel of usama's hideout in Pakistan, how can anyone disputes its effectiveness?

Mostly because it didn't. All the waterboarding told us is that Osama had a currier. Did you not know that before the torture? How do you think all the tapes got to the press? That should have been your first clue, no waterboarding necessary. We found the currier with no help from the Bush administration, we tracked him, (again, no help) and The plan was conceived, practiced, and executed, all while Bush did nothing but hide from his legacy, afraid to go overseas because he'll be arrested for war crimes.