I don't have a problem with players withdrawing from internationals due to illness and then playing for their club team when their illness has improved.
But anyway, this protracted debate is about you not believing that Murray had an illness. Personally, I'm inclined to believe him as it wouldn't make any sense to withdraw from the previous tournament, even if he's determined not to play in the Davis Cup (which is also up for debate). Ultimately none of us really know about his state of health, and what happened prior to the tie in Argentina doesn't help us with that.