The AMA Chief Counsel's testimony is evidence - as opposed to what you've posted, which is purely hot air.
And as for the reasons for the ban, at least as interesting as the testimony itself were the Congressmen's responses: our minds are made up so don't confuse us with facts.
What I did here was to explain *exactly* what the doctor meant and the implications when he said that the AMA has no evidence. He really did mean that the AMA had done no studies and so did not have any data. He meant no more and no less than that the AMA had no data. It is not my problem that you do not know how medical professionals think or communicate, and that you do not understand how precisely they communicate.
I'm certain that the pro-legalization advocates love to take that statement out of context and interpret it to mean something that the doctor did not intend. That doesn't change the doctor's meaning, and it does not mean that marijuana is perfectly safe (and it is clear that the ultimate goal of the pro-legalization advocates want everyone to believe it is completely safe and harmless).