Skimming the decision, it turns out US does not have a liquor license to sell booze in NM. It has over served at least two pax who de-planed in NM, and at least one of them was drunk enough to kill himself an a family in a car "accident".

While I think responsibility should fall on the drinker, and I think liquor licenses are a bad idea, nonetheless, the decision is legal (and applies only to segments that land or takeoff from NM).