Who will avenge Van Spronsen's death?

https://www.buzzfeednews.com/article/briannasacks/ice-detention-attack-killed-washington-antifa-manifesto

I think for every murdered antifa we must kill 1000 ICE officers, together with their families. Only then these racists will repent.

That 17-year-old, who is now 18 and a lead organizer with Seattle Antifascist Action, told BuzzFeed News that Van Spronsen was active in a number of far-left communities in Seattle, but "no one saw this coming from him" because he was "soft powered."

Anybody else have no idea what "soft powered" is supposed to imply?