Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits. Matthew 7:15-16
The suffering in some people is so denied and undignified that they borrow the suffering of an entire group and use it as a cover. In the 1960s, my mother was involved in the civil rights movement – as much as a woman with four children under six could be. She would march and vote on the side of social justice and she believed deeply in equality for all. She was following her values, and although she had her own style of exporting suffering, social justice was not her chosen outlet. At the same time as my mother was waving street signs, a group of women blew up a townhouse in New York City with a bomb meant to kill the sort people my mother was marching to convince.
It doesn't have to be bombs. A person who types furiously on the internet spilling hate and accusations can be as good as exporting suffering as someone who cold-cocks an opponent at a university. People collect other people's injuries - a beating here, a shooting there - and stroke this suffering like a lap dog but never train it. And others merely stand, quietly seething on a street corner, next to someone innocently waving a sign.
From the perspective of sitting with suffering, all exported suffering is similar. Beatings and shootings, fear of strangers, expectations of violence take their place on a continuum that includes name calling, spitting at, glaring or attempting to guilt. The suffering that is exported will either continue to be passed on or leak until it is processed. The fruits of unprocessed suffering are always suffering. It is possible that the white supremacist or misogynist or non-minority target that the "justice hero" exports their suffering to will find a way to sit with their suffering and release it as love. But what is being exported is exactly the same as the thing it purports to be fighting.
People who rage on behalf of the oppressed are enjoying the process – they are a snarling dog with a wagging tail. They are likely to become quite aggressive if this is pointed out. They are trafficking in their own suffering and denying it at the same time. You don't get to this state if you are willing to work your own way though.