Part of the benefit of UBI is removing a large amount of overhead that comes with current welfare systems. This is done by writing a check to every citizen in the system with overhead only to confirm that one citizen gets one check. When you add in other checks you increase how much money needs to be spent on just running the system
If I literally see a dime from the UBI check and pay $2 in taxes to support the UBI program for every dime in UBI I receive, it's reasonable to say that I'm not really receiving UBI on a net basis.
(I still support it, and your arguments for why it must be universal are congruent with my own thinking.)
That's completely true, it's just cheaper to send the same check out to everyone than pay for the administrative costs to figure out who gets the check that week.
