I wonder if the recent (very low) sulfur standards for automotive diesel might be pushing more high-sulfur crude into jet fuel production. (I doubt any crude can meet the new diesel standards without additional processing, but it seems reasonable that it would be easier if you had less sulfur to start with.)
Actually you have the right effect but the reason is different. Typically, Jet (whether Jet A or Jet A-1) is sold to a spec and the parameters are strictly controlled. In the case of Sulfur/Sulphur (S) the spec is, in theory, independent of the source crude, its just that the refinery will need to carry out additional processing (e.g. by hydrotreating) if the source crude is high in S. Its not just elemental S either - it is active S compounds such as mercaptans and the spec has come down over the years, which is why you have seen many "Jet Merox" plants bolted on to Refineries in the ME for example over the last 20 - 30 years to reduce these S species. High levels of active S compounds like mercaptans cause the fuel to fail the "Doctor Test" and are bad news in Jet.
The problem has been that as road fuel S specs have tightened, hydrotreating has become oriented to the biggest cut (diesel and catalytically cracked gasoline) where mercaptans are less critical. As more gasoline selective hydrotreating units are placed on stream, the levels of mercaptans in the higher fractions like Jet have been rising. But the spec willl still have been met, probably through additional after-treatment.
We continually see specs tightening in response to better engine technologies (and even environmental initiatives eg from ICAO) as well as problems like the introductions of road biofuels which caused the bleed of biodiesel or "FAME" from multi product pipelines into Jet. You need to be a bit careful of characterising S as "the enemy" however. S does provide lubricity for injectors and the New Zealand case where ultra-low S Jet caused serious problems in the domestic fleet (not L/haul which only filled up in NZ on departure) is instructive.