It will drive a further wedge between the producers and consumers in society, which plays right into the class warfare rhetoric that the politicians who would support UBI are always fomenting.
Who's going to pay for UBI? Everyone! I see the amount of $10,000 thrown about. There are 235 million adults in the U.S. That's $2.35 trillion per annum, more than 13% of the GDP. You don't think the taxation required to generate that kind of money won't reach far down into the middle class? Dream on.
And we are going sacrifice $2.35 trillion for what? It won't increase productivity. If anything it will reduce it somewhat. Yes, I'm ignoring the benefit it will be to the truly needy, and that's important, but for the majority of the country, the UBI will be way more offset by the much higher amount they have to pay in additional taxes.
Social cohesion, my ass.