The book of Deuteronomy/Devarim begins with the Rebuke – ' To'chacha ' by Moses of the children of Israel as part of his final address to his people before they enter the Promised Land under the leadership of Yehoshu'ah. The To'chacha-rebuke seems pretty mild with Moses hinting at the major sins like the sin of the Golden calf-' cheit ha'eihel ', the Spies, Korach's rebellion against the leadership of Moses and Aaron, by just mentioning the names of various places and locations where these sins were committed. The Torah also tells us that Moses addressed his people after Moses himself had conducted the war against the feared Amorite kings, was victorious and conquered land which would become part of the land of Israel.
The questions that need to be addressed are (1) why did Moses not mention the sins explicitly and just alluded to them by using place names or other veiled references ? (2) what is the significance of the timing of the speech after Moses' victory over the Amorite kings ? (3) The rebuke- to'chacha seems to be out of place, because it is directed against people who were not alive or at most were under 20 years of age at the time of the major sins. Only the sin of Ba'al Pe'or took place near the end of the 40 years in the desert. And still Moses said to them – your eyes have seen how God destroyed Ba'al Pe'or and those who served that idolatry, but you who cling to Hashem- God are alive today. So the people standing before Moses are those who did not sin with regard to Ba'al Pe'or or the other sins.
So to start with the 3rd question . The people standing before Moses may not have committed these sins but on a simple level Moses could be warning them , that if their parents sinned while in a holy environment surrounded by miracles, how much more aware of God's presence they need to be in their new environment. On a deeper level , R' Isaac Sher explains that a sin has its roots in a person's inner being. A person can then give expression to his 'pnimiyut' – internal being in various ways including the actual sin. In the book of Joshua - Yehoshuah 22:17 , Pinchas rebukes the tribes of Reu'vein and Gad saying - 'is the sin of Ba'al Peor too little for us, from which we have not been cleansed until this day and in the same way does the prophet Jeremiah 2:23 – Rashi. The people standing before Moses might not have actually sinned , but on a deeper level they had not yet been cleansed of the sins of the golden calf, spies, Korach , Ba'al Peor etc .
To'chacha –rebuke and criticism are given in the hope that people on the receiving end will ' internalize ' the message and underlying values . Teachers and parents forget that they were once kids and think that in order to emphasize the seriousness and severity of the offence they need to use strong language, a loud voice and even use threats of punishment.. The truth is and this is well researched , the greater the external motivation used , the less internalization of the actual message and underlying values takes place. Kids in a kindergarten were told not to play with toys if the teacher was not in the room. One group were told that they would be punished if they disobeyed and played with the toys. Both groups did not play with the toys but the group that did not receive the threat of punishment internalized the teacher's message more than the other group. Likewise parents are told , don't discipline out of anger , because the only message that is internalized is the anger and not the message itself. When we criticize or rebuke we need to remember – it is not what we teach them that matters, but what they learn – and often it is that as a teacher or parent you are unfair and don't understand them and have an anger problem. So Moses was being sensitive to their dignity and their situation .People generally already feel bad about what they did, so one does not need to pour salt on their wounds. Criticism and rebuke generate a ' counter- will' in people. If Moses would not have dirtied his hands and fought in a battle and won , people could have challenged him – what right do you have to rebuke us , have you brought us into the promised land as you promised? Moses wanted that the children of Israel would internalize his message. It meant that they had to reflect on the deepest level to see how they still had not been cleansed from those sins and they still were present in the deeper personalities. This requires a person to feel privileged to be guided by Moses in doing some soul searching and becoming closer to God. This could take place only if Moses would respect their dignity, be sensitive to their sense of shame and guilt , appear to be sincere and at most hint to their sins.
As an alternative to criticism we should just in a neutral tone describe what we see without any judgment. Even better is to reassure the child that we are not angry or going to punish him , we just want engage in collaborative problem solving . In this way the child will be able to internalize and reflect , be part of the solution and in an autonomous way engage in the moral act of restitution.