In my head the basic argument for UBI goes like this:
Anyone who’s ever filled out a forms to get a welfare payment or a low income tax credit knows what a drag it all is. Then it’s a massive drag for someone to read it all at the other end and administer the payments. It is humiliatingly intrusive one side, boring make-work the other. Enough of it. The idea of welfare (in the UK at least) incorporates the idea that there is a certain decent minimum needed on which to live. Just dob everyone the cash and be done.
Also, poor people spend cash better and more wisely than rich people: they have to, and this would mostly be an even local spend on goods and services, making the real economy turn. Would making poor people a bit richer be inflationary? I say, let’s try it and see. Could always tweak it in the light of experience.
As for abolishing public health and education services to pay for this, such services have to be organized somehow, and doing so collectively is objectively the superior approach. Compare the share of GDP consumed by health in countries with liberal health systems e.g. USA, France, and those with proper public systems e.g. UK, Scandinavia. The latter are both cheaper and better, because better info and more rational organization are possible, and sophisticated purchasers (e.g. UK’s NICE) keep the lid on the private gouging of e.g. the pharmaceutical industry.
I do share your concerns about those on the libertarian right looking at UBI who are also pushing an agenda of private healthcare and education. They probably dream of folding their horrible voucher schemes into the UBI debate. But then they’re generally in the US, and so probably have impoverished imaginations about what high quality universal public services might look like. Consumer models for purchasing health and education are inevitably feeble, because of the high transaction costs for an individual who seeks to (rationally) evaluate “competing” “products”.
That’s a distraction from the main UBI issue though, which is surely also about liberating junior civil servants from the tedium of “evaluating claimants” towards more socially useful work.
Your post has reduced my esteem for Graeber BTW. It is not good enough to dismiss someone’s contribution because they are “a fanatic”. Play the ball, not the man. Tsk, tsk.
