> This is the thing I really don't get about UBI. It really, really doesn't remove means testing. Your tax burden is still means based
There's a degree to which this is true, but there is a radical difference between tax system "means testing" and that with existing means-tested public benefit programs. With existing poverty support programs, its quite possible to lose nearly (and in some cases even more than) $1 in public benefits for each $1 in outside income (and much more at certain breakpoints), and to do so while your total income is under the federal poverty level.
OTOH with stae and federal income and payroll taxes together, you can -- in a relatively high income tax state like California -- currently reach a maximum marginal rate (including the employer share of medicare taxes, and assuming that payroll taxable income and income taxable income are equal, which both overstates the tax rate on nominal income and ignores minor differences between the income those two taxes apply to) of 55.8%, but it takes $1 million in taxable income to reach that point (some UBI proposals would add higher maximum marginal rates, at even higher income levels.)
So, sure, the tax system reduces the incentive for earning additional income, especially at higher income levels; the problem UBI address is that existing poverty support programs do much more to reduce the benefit for earning additional -- or even any non-benefit -- income, and they do it at poverty levels.
(And, on top of that, they add -- with each program -- additional layers of bureaucracy to enforce those rules, rather than letting the tax system be the single point in which means are considered.)