How is it fair? You do give the same amount to everyone, but you do not take the same from everyone - you have to take more from those who chose to work. Hence the unfair part.
Taxation is quite separate though - we all have the same access to government provided services and infrastructure regardless of how much income tax we pay, I don't see anybody arguing that's unfair.
A just and civil society being one where the harder I work, the more taxes I pay? Where stores are closing right and left because theft isn’t prosecuted but I have to pay $7,000 to get a bathroom permitted while an RV on the street outside my house is considered a home and gets to dump shit on the street with no repercussions?
> A just and civil society being one where the harder I work, the more taxes I pay?
How about: a just and civil economic system is one where the more utility I produce the higher quality of life I can achieve?
This is very different from what you implied (being punished for creating value). Taxes and UBI aren't in opposition to this. It still rewards production and those that create value. It also recognizes that hard work isn't always valuable (digging a tunnel with a spoon is harder than with heavy machinery. But the latter provides more value). Maybe we should frame things this way instead. Progressive taxes do not result in situations where a raise in pay causes a decrease in take-home money. It does instead address the issue that money is sticky and the mere existence of capital passively generates capital (which actually means you generate wealth without doing work). Fine at certain levels but clearly can get out of control (generate wealth for retirement vs generational/perpetual wealth where your children end up wealthier than you passively).
Again, nothing to do with whether UBI is fair. I accept progressive income taxation isn't fair and in fact I'd rather we did look for better ways to structure how tax is collected. An ideal economy wouldn't tax income at all - why discourage people from earning money? And if a UBI could do better job of reducing extreme and destabilizing levels of inequality, we could probably do away with income tax, and tax things there's a reason to discourage instead.
Only a--reasonably and relatively; no society is perfect--just and civil society provides (over a sufficiently long time horizon) the kind of stability and structure that allows the rich to stay rich. Which doesn't mean that you can't get rich in other societies, of course. But, broadly and historically speaking, having to expend those riches directly on men who will harm and kill for you has something of an expiration date, usually around when they realize they can just take more than you'd be paying them.
That's to say that functional courts and a state that acts as the only legitimate applicator of force tends to be a lot better for the rich, and those too fall (or themselves turn on the rich, too) when they stray too far from the line.
> you have to take more from those who chose to work
Not the right framing, but not far off. It depends where you set the threshold and how much you extract. Remember that money is a resource where positive feedback loops exist: "you have to have money to make money", "the first million is the hardest", or "passive income." We can think of money as sticky and attractive. Momentum matters. Also remember that a capitalist market relies on competition and money to be fluid and constantly exchanged. Transactions are not zero-sum, but many times result in a positive value. This is even true in a pure fair transaction and without considering external costs like taxes.
tldr: there are sources and sinks in the economy and this is conditioned on the value in the previous time-step. Capitalism works well when value is continually exchanged: meaning sinks are bad.
Once we consider these things, "fair" gets more complicated. One can argue that it isn't fair that wealth begets wealth. That certain goods have an economic value that is not being captured by the evaluations, and are often difficult to put price tags on (e.g. air quality). Tragedy of the commons is quite real. One can also argue that it isn't "fair" that the system does not optimize for societies and instead optimizes individuals. Fair is difficult to define and none of this is as easy as it appears on the surface. Both pro and anti-UBI people make these mistakes. I'm not attacking a particular side but rather suggesting this isn't as straight forward as you have characterized.
It's fair to the extent that anyone can drop out and have the remaining workers pay for their livelihood. As more people do this, the more rational it becomes, and the closer to economic collapse we get.
If there were evidence that a substantial percentage of people would simply opt out of contributing to society at all but it still required considerable levels of human labour to support the standard of living a UBI is expected to provide then I would absolutely be against it. I don't believe the former is true though, and the latter will continue to become decreasingly so, to the point automation etc. will generate more than enough goods and services than we need for everyone to enjoy decent lifestyles.