Shame on WT for having a "rule" that you must shun disfellowshipped family or face shunning or disfellowshipping yourself. Shame on parents that comply.
DFed or DAed may not have a choice if they are shunned by others as you cannot force someone to acknowledge, greet or show common decency towards you, but, JWs do have a choice whether they shun or not. It might not be an easy choice and there will be consequences but it is still a choice.
Anyone who chooses to stand up and do the right thing will face the consequences of disapproval by others who don't like it.