If you can persuade some congressional committee to fund NASA to develop, launch, and maintain the probes then I'm sure you'll find no shortage of people willing to pay the taxes for it all.
I happen to agree with you, and would be happy to see taxes allocated towards further exploration of the solar system. But resources are limited.
I wouldn't call this abuse - it's a marketing tactic, and it's rarely hard coded, more likely selected by default - at least that was my experience.
Just to add some numbers for perspective. In 2018 there was 763M PLN (~$200M USD) to split among 9000 approved organizations. The largest one got 166M with another 100 orgs getting 1M+.
It doesn't work exactly this way in France, but any donation to a registered non-profit gets you a 66% rebate of that amount to your income taxe (within a 20% limit of your taxable income).
Yeah, it's the same in the result, but the barrier of entry is significantly lower (easier to fill 1 field in tax form once a year than to make a payment and then get a refund).
We don't get a refund (perhaps I misused a word in my last comment): when filling my tax, there's a box for amount donated, which is then used when calculating the amount of money I'll have to pay as taxes.
But yeah, the barrier is higher, but I think the choice of organizations is wider in our case, like the organization to which I gave money the last two years wouldn't be on the list for example.
I happen to agree with you, and would be happy to see taxes allocated towards further exploration of the solar system. But resources are limited.