Are you suggesting the US should fund a global UBI?
The US has used cheap labor globally for decades, why would the blue collar worker in Indiana qualify more than the blue collar worker in Indonesia? Both are making goods for American billionaires and both are struggling.
To take a simple example: within a country, if you send the UBI money to a local government for disbursement and the local mayor/governor just pockets it, he's still ultimately subject to the legal system of that country and can be jailed, etc. There's no international equivalent of this. If you send some UBI money to Poor Country X for disbursement and the local governor pockets it, there's nothing you can do except not send any more money.
Humanity doesn’t really know how to do global policy, even if there are massive potential benefits.
Of course people usually try to draw the UBI Venn diagram such that they are a net receiver of funds.
Equality to them means them getting more material goods, not them giving up more material goods.
What they are really saying is "I don't want anyone to be richer than I am but fine with people being poorer". So the default human position on things.