Between existing regional inland refiners, and coastal refiners, improvements in those plants, and a decline in demand, U.S. refining capacity exceeds that demand. Combined with supply side stability, there is no need for additional capacity, especially greenfield.
MMEX does not fit in the market landscape within the U.S., and they state that fact, given that their ultimate target market is Mexico, specifically northern Mexico (or as confused Jack, either drunk or having a senior moment during his KWEL three-stooges interview said, western Mexico...).
Sadly, MMEX's lack of understanding of the refining sector, the export market, and factors like being unable to reach the target customer guarantee that no topping unit, or complete refinery will be built - at least not by MMEX.