So when people dont have the ability to earn through work since automation replaced them, how is there voluntaryism?  When corporations are earning more money through the development of AI and robotics, do you think that leads to move voluntaryism?  

And it is ironic that you mention this as your reason for being against it when UBI actually encourages voluntaryism.  Do you think most people who take a job at McDonalds, work in an customer service center, answer phones in an office, or work as sales people do so because they love what they do and voluntarily do it?  Or do you think they take those jobs AND remain in those jobs because they need the check?  UBI gives people the ability to say no to garbage/slave work.  

This is the reason free market guys like Charles Murray, Milton Friedman, and Friedrich Hayak all support/supported UBI.