Not every billionaire built their life doing something unethical. Killing them wouldn’t make you any better. People also fuel monopolies out of convenience even if they have a choice to act ethical. We should strive for legislative change. The billionaire might be the owner of parts of a company, but we as a society use the services for our daily lives. What economic system that actually works also supports free ideas, innovation and the willingness to perform other than something based on capitalism (Communism never worked and doesn’t reward it properly). Treating symptoms won’t treat the cause. We need legislative change.