Most of your post is just B$ and hot air, although strictly speaking I can't say you are wrong. But above all you are not really disputing my points in my previous thread.
For instance, tax loopholes. The definition of a tax loophole is "A provision in the laws governing taxation that allows people to reduce their taxes". That is basically what a tax preference is. But whatever you want to call it. My point is that the economic substance of a tax preference is of a government spending program, even though a tax preference doesn't show up on government spending outlays. The mortgage interest deduction for example is basically a government subsidy for home (and vacation home) ownership. I think you were acknowledging that saying it exists to achieve an "agreed upon social policy".
For purposes of this discussion I don't want to argue over whether we should allow deductions for mortgage interest. But my point is that you have options. Tax preferences should be put on the table with all the other government policies and the questions should be applied to it "how do we afford the cost of this?". "Can we afford it"?
On the issue of financing tax cuts. I think we basically agree, we just differ on semantics. As long as we agree that government spending has to be paid for.
I take issue with your notion that taxation is necessarily on "productive activity". Actually the core of our income tax system is very sensible. We give businesses tax deductions against their income on pretty much all expenditure used to produce that income, Moreover, we provide standard deductions against any net income and then apply only a graduated tax rate after that. So a lot of income taxes is almost by definition non productive income because the productive part has already been deducted.
The problem I have is that over the last 40-60 years is that FICA taxes have increased. That is a tax productive income. Its a tax on labor starting at dollar one. At the same time "free trade" policies have allowed U.S. multinational corporations to use communist labor and the same time taxes from that income has generally decreased. That trend needs to be reversed.
As for SS and Medicare. Look, there is nothing sacred about those programs. But the fact is, they exist for a reason. The depression in the 1930s happened and it could happen again. Wise people in the 1930s with fairly broad bipartisan support thought SS was a good idea to create some kind of secure source of income for elderly to fall back on if their savings disappeared. It actually provided a backstop so that businesses could be allowed to fail and created purchasing power when the economy was in a deflationary spiral. As far as I can see that program is needed as much as ever in today's world. The same applies to Medicare although that program came later.
So I don't think SS and Medicare should be cut, unless its through means testing using people's accumulated wealth and cutting inflation that SS recipients never asked for or wanted. BUT, if you were to cut SS and Medicare then the money saved has to go back to FICA taxpayers. Money cut from SS and Medicare doesn't belong to the defense department or any other discretionary program nor should it be used to give back to those who pay regular income tax.