I believe they mean not that they were wronged, but that the system is wrong. Ala MLK just laws and unjust laws. They disagree with IP law and thus feel piracy is fine as such.
Personally, I pay for my music and don’t use streaming services. I support bands by going to shows and buying merch. However I also don’t listen to big name artists and shit, and think most really don’t give a shit if you pay for the music or not if you’re supporting them in some way often. Plenty of bands have a “steal this record” or “steal this album”, or end up putting out stuff where they’d urged people to pirate their shit example: Streetlight Manifesto had done so because victory was refusing to send CD’s to the band to distribute to those who had preordered, wasn’t paying them for purchases made through victories site, etc. The (bigger label) music industry is fucked. They extort bands. They extort venues. They extort anywhere that plays music. They extort anything they can for money while the content creators barely get shit.