They don't get angry because the WTBTS has convinced them that if a child falls away, the fault lies within the child, not the parent and certainly not the bOrg.
The bOrg does not feel a need to provide for the cult children because "having the truth is enough." Children are expected to behave as miniture adults and sit still for 2+ hours and listen to things they don't understand. Teenagers are seen as feral beasts and can only be managed with a heavy hand.
I keep bringing this up, but when I was 14, I became severly depressed (b/c of growing up in this insane cult). Since JWs were not supposed to be depressed or have any mental health problems, some in the congregation decided I was demonized. I lost all my "friends" and instead of becoming enraged, my parents took the stance of 'they're wrong but you have to tolerate them and really, ultimately they're right.' So, I was "shunned" without being DF'd or DA'd!
That of course pushed me over the edge and I attempted suicide which made things worse.
Only when my depression abated, did these "true friends" and "spiritual brothers and sisters" talk to me again.
What bullshit.
My folks never once became angry even though 98% of what happened to me was because of the bOrg and other JWs.