"Can anyone explain why a SANE person would take synthetic testosterone, knowing they test for it?"
That would go for any sportsman taking any drug that is tested for.
However, history shows that many of them do exactly that.
Athletes do not get
the same education that
"normal" people get.
Match a stunted brain
to a hormonal system
freaked from doping, then
you get a young man
who makes decisions that don't
stand much scrutiny.
It was a horse drawn buggy a few years ago.
I've wondered that too. Why take something if you know you're going to be tested? Or is it that they are tested at random times throughout the Tour and so Landis (if he is guilty) figured it was worth risking it since he was in a desperate situation at that point in the race? Another possibility is that he thought he would able to beat the system - that he had some way of masking the banned substance but for some reason the mask failed to provide cover for him.