Plausible deniability isn't the same as a thorough debunking.
MY PERSONAL OPINION is that there were casualties, that the raid was poorly planned and executed, using Delta personnel in ways that were not consistent with their training ("Big, noisy ops" are not their cup of tea).
And the intelligence was bad.
Call the Taliban what you will, they are and have been fierce fighters. That's why they were able to overcome the OTHER "fierce fighters" among the many factions of mujahedeen that were vying for control of Afghanistan, and hold power for five years--an eternity in politics in that part of the world.
We stubbed our toes, we didn't (I hope) get anyone killed, and we learned a valuable lesson.