Reading posts like this leaves me feeling angry (that it happens at all, this day and age), bewildered (what kind of callous jerkwad sends death/rape threats to a stranger over editorial content) and helpless (what can I do to help or prevent this from happening further?)

I give credit that there is a problem. I genuinely want to help improve things (my daughter might want to follow her old man into this field one day). What can an unassuming white developer do beyond publicly stating "This is unacceptable", and setting the right example of personal behaviour?