No one is going to be like, "oh, I guess what I was thinking was a loophole isn't really a loophole. So, I'm reversing my prior view and now think it's great for Warren Buffett to pay a lower tax rate than his secretary."
i'm aware of this anecdote, but i don't know the specifics of buffett's income in that year.
regardless, the main reason buffett doesn't pay massive amounts of taxes are 1 (and about 99% of it). he doesn't realize most of his potential income in any given year, and 2 (and like 1% of it). most of his realized income is presumably capital gains which is taxed at a lower rate than ordinary income.
so i would not characterize that difference as a loophole. the capital gains and ordinary income rates are headline items. like among the top 3 or 4 most salient features of the tax code. calling it a loophole when it's been a featured point of our tax code for as long as i can recall doesn't make much sense to me. hell, i can remember board socialist kat kid defending that feature in a previous tax discussion when i was advocating for higher rates on capital gains.
more to the point. the discussion mir and i were having was touched off by a disagreement as to whether taxes were being deferred or avoided. in the case of buffett, they are very clearly being deferred (i believe he's stated that his plan is to eventually avoid most of those deferred taxes by giving away all his money, which debate if charitable deductions makes sense as tax policy all you want, but as a super clever and nefarious scheme to not pay taxes, giving all your money away just doesn't impress me much)