UBI is based on the idea that some people will still want/need to work. It is not related to freeing people from work, but to ensure that people's basic needs (housing, food, health) are met even if, for some reason, they are unable to work. Usually, UBI proponents claim the main difference between UBI and the current nets is that it would simplify the administrative control structure.
The intent of UBI (make sure everyone has their basic needs met) isn't different from the current safety nets. And, of course, since shit has to be made in order to be consumed, UBI requires people to keep working.
> Voters. Voters have collectively decided, in all developed countries [...] I am trying to explain that there are good reasons why we do that; it is not a moral failure.
It's not a once for all choice, though. Safety nets in all countries have evolved gradually, and are still evolving. Opposing yesterday's voter choices to today or tomorrow's activist hopes is a misunderstanding of the way democracy works. Every choice voters have made about social nets in the past happened because someone started saying "we have the means to do this, why shouldn't we do it?"