"Other people are stealing, so it's ok for me to steal" is not how morality works. I think you can use the Government defensively but only if that use doesn't infringe on natural rights.

Note that with a bit of creativity, he could still protect his business and stay moral. E.g. allow companies and individuals who are anarchists and act like anarchists to do whatever they want and disallow statist from using the code. So if Apple wanted to copy their code they'd have to publicly state they are anti-state and release all their patents and copyright. I doubt they'd do it for a few lines of wallet code but even if they did it'd a massive win for freesom.