Itzick,
What are you talking about? We have a responsability to help another jew if they need it. If a kid dosnt keep kosher and by humiliating himher you cause them to turn to drugs and they destroy their life it is wrong to humiliate them. Alot of people who go off the derech dont want to be part of the community because of the greatness of the community itself, but rather because their family and friends are part of it and they despite evreything still like their family.
What do you gain by making them feel bad?
Would you rather your kid be frei and o.d. on heroin, or be frei and at least live?