If one of the parents is extremly irresponsible, the more responsible parent should have custody of the children and be in complete control over any contact between the children and the irresponsible parent.
I would agree with you if Tiger were "irresponsible" in being a drug addict or a criminal which would threaten the children's well-being. He has proven himself to be pretty "responsible" in providing his family with a lifestyle few in this world have ever experienced. If Elfin had had an affair nobody would be talking about Tiger "controlling any contact between the children and the irresponsible parent"....she would get custody with the full support of the court system and folks like you. Everyday...all across this land females have affairs and take the children away from their father to live with the man they are having an affair with.