Families have become victims of harassment when weirdos have sent images to them of their dead family member.

Most people would be offended if I pissed on their mother's grave.

Let's say they can't be re-victimized and their families aren't new victims. There's still the argument that it encourages more killings.

I believe that videos like the Christchurch massacre should be banned. That video was made by the murderer and I'm sure was intended to bring fear to that community and encourage more acts of violence by other murderous weirdos.

A surveillance video or a video made by a victim or bystander is different. I don't think those videos should necessarily be shared, but if they're not made by the perpetrator or shared to try to bring support to the preparator, then yeah it's probably newsworthy. Still, the victims' families should be taken into consideration. I'm sure you wouldn't want to be scrolling through Twitter and come across a video of someone you know being murdered.