If he is just suing that company, it's really about himself and his interests. He is right to notice the moral incongruence but he can't expect other people to support him in his personal quest to get justice just for himself.
What he sees as gross abuse is just day-to-day reality for the vast majority of open source developers. Many of whom struggle to get by and struggle to find jobs.
Companies which refuse to even extend OSS devs a job interview are making out like bandits on top of their work while simultaneously using VC funds to raise entry barriers and ad costs so that the OSS devs cannot even compete in their own industry which they contributed to. The typical skilled OSS dev ends up with no jobs, no funding, no opportunities.
OSS devs can't even afford legal representation so legal precedents are meaningless to them.