. The problem lies only with the quality of oil on the market, as a small proportion has too much Sulfur in it, and can't be used for every purpose. The better refineries (ie those in the western world) Have no problem using this oil. So whats the problem? The answer is there isn't one, only some wish to make the perception that there is one, so they can make a lot of money on the backs of ignorant investors.
From what I heard from an 'expert' on the radio your first 3 points are correct but the one above is dead wrong. He considered that many $$ needed to be spent to improve refineries to treat sulpher oil. Any good for pouring on the roadways & the like. The 'missing' 2m odd barrels were just that -missing, hidden stored away for a rainy day a la John Denver & Jim Sinclair.
I have taken a position in diesel & a 4l can of oil.