Giving a small number of people an amount of money below what they'd need to actually survive, with them knowing perfectly well it won't last forever has effectively zero in common with UBI. Give an entire contained population of people enough money that they can have all their basic needs met just with that money, and guarantee them it will continue for the rest of their lives, and I'd bet quite a lot that the results would be drastically different.
Also, not a big deal since you also provided two reasonable links, but many people will see that you linked motherjones and likely discount your comment entirely. It's on the same tier as OANN and breitbart.
By your own measure, basic arithmetic has roughly the same insight into the impact of UBI on society. As is judgement and diversity of life experience. As you say, empiricism on its own is nothing.
If anything existing basic income experiments have revealed the opposite:
https://www.pbs.org/newshour/show/stockton-ca-gave-residents...
https://www.bloomberg.com/news/articles/2021-03-05/what-did-...
https://www.motherjones.com/politics/2014/06/richmond-califo...