Moly in the form of molybdenum disulfide powder is a popular and sometimes only option for a lubricant in many industrial applications, including metal forming, dies, stamping and general lubrication in high temperature conditions or where the environment would mess up a wet grease or oil. It's also used in electronics for physical switches and relays, even in aviation systems. I believe before they could make low sulfur graphite, graphite was replaced by moly as a dry lubricant in aviation applications. Moly can withstand high temperatures, and thus even trace amounts of free sulfur are easy to remove.
I've never seen any other sulfur compound or elemental sulfur listed as a trace contaminant in commercial moly powder, so it must be below 20 ppm (parts per million). By law because of the applications in which it is used, dry moly and its preparations sold as a lubricant must have a maximum acid value (KOH MG/G) of 0.5, the same as fuels, oils, greases, and any other products that come in contact with critical metal components that are vulnerable to corrosion over their lifetime.
Here is a typical information sheet for the cheap grade of dry lubricant moly.
Moly powder suppliers often claim that it actually prevents corrosion - not causes it. Imagine the lawsuits if these moly products instead were shown to actually ruin expensive industrial and commercial metal parts by increasing corrosion?
Thus in my opinion that old alarmist article saying how moly turns into sulfuric acid and pits metal is a bit of an exaggeration at the very least. There are no such product warnings for use of dry moly in these critical applications involving metal lubrication, and if there were it could obviously not be used for those applications, particularly where the lives of humans would be put in danger otherwise.