For an overly reductive example: a rich person could support higher taxes (including his own) to be raised to a level that could feasibly fund a social safety net on par with a UBI. If he were to unilaterally provide his portion of higher tax revenues, the government wouldn't instantly implement a minuscule, partial increase in the safety net. OTOH, a consistent tax regime based around a consistently higher revenue base is a fiscal environment in which we could move further towards this person's preferred policies.
(Note that I'm making no endorsement or rejection of the specific policy described above, just using it as an example to point out how nonsensical the complaint in this thread is).
I'm not saying it is irrational for the author to advocate raising taxes for everyone, including themselves. I'm saying that if the author really thought donating that extra $X to the government (when other people do) was such a good idea, they would be donating it right now even if other people don't. The reason is that the marginal benefit to the government of the author handing them an extra $X when other people do the same is no higher than when they don't.
Unless, of course, the author plans to dodge the tax themselves once taxes are raised for everyone.
The prisoner's dilemma is not a valid comparison because donating when the other person doesn't yields an equal or higher marginal return as donating when the other person does. In the prisoner's dilemma it's the other way around: cooperating when the other person defects results in a lower marginal return than when the other person cooperates.
This is an aspect of human behavior. Sometimes people won’t do something if they aren’t forced to even if they think its a good idea. This is why the free rider problem exists. Your conclusion ignores facts surrounding human psychology. People don’t see a $1,000 donation to the government as being helpful if it’s just them doing it. They can see it being beneficial if millions of people do it. Hence an individual is unlikely to make a voluntary donation to the government whilst supporting increased taxation for everyone in their income bracket.
Which conclusion? You basically said I'm correct.
> if the author really thought donating that extra $X to the government (when other people do) was such a good idea, they would be donating it right now
Which part are you disputing? Your comments about human psychology merely support the fact that the author doesn't really think it's a good idea, and that there are psychological factors other than rationality and honesty at play.
If you're familiar with the prisoner's dilemma, which is a toy, two-party example, there's a massive difference between coordinating cooperation and unilaterally taking the cooperate action.