Years upon years of brainwashing and indoctrination through constant repetition are extremely powerful. Also add in the influence of scrutiny from peers and a possible reporting on one another to individuals in the congregation and it makes it difficult to behave any different for JWs. They have been taught that this is loving discipline from God who is trying to bring you back to the fold.
Don’t feel bad, mothers and fathers will cannibalize their own children for decades if necessary to prove their loyalty to a small group of imperfect men that tell them to do this. Incredible to believe that parents will throw all those years away in shunning and silence towards those they gave life to and brought into this world!