can you elaborate on this capital gains tax loophole?
Closing the capital gains tax loophole is, presumably, a reference to stopping some or all of this favorable treatment.
2. Changing that would not do anything to solve this problem (even if you think it should be solved through more government spending, it wouldn't raise much money)
(I have advocated better aligning the treatment of capital, labor, and generic other income, but the details involve more than just counting long-term capital gains as ordinary income.)