...”Can’t we just put a line on tax forms wherein these people could simply write in how much additional tax that THEY would like to pay, and leave the rest of us alone?”
Sorry, no. That would be a violation of the primary tenet of liberalism. This foundational concept can be summed up in the common philosophy as: “We have a problem, and You have to pay for it”
That would be a violation of the primary tenet of liberalism. This foundational concept can be summed up in the common philosophy as: “We have a problem, and You have to pay for it” AND, the political corollary: "Vote for me, and I'll get you benefits -- and make somebody else pay the tab."