Care to expand on that?
It leaves a mess in your barrel, on your hands, in your press, and potentially could attract moisture if left uncleaned after firing. There are much better options out there than Moly, it was used over other lubricants at first because it was cheaper than other dry lubricants. Now that Moly prices are just as high as other quality dry lubricants there really is no reason to use it over other dry lubricants out there. Biggest issue with using other dry lubricants is there is only one company in the US that makes a non moly bullet coating, and their consistency is poor from batch to batch due to the consistency of their raw materials. I am sure there are places you could have coatings mixed to your specifications, but it would probably be cost prohibitive, and you might not get enough of what you need when you need it if you aren't ordering enough. Too bad that the coating on black talons got bad press as a cop killer bullet, it was made with PTFE suspended in alcohol that made a very consistent coating from batch to batch.
Moly does lubricate,there are just better options out there now. New coatings are coming to the US from other countries that will far out perform Molybdenum disulfide and leave a clean barrel. I personally don't want to have heavy deposits of Moly in my barrel I have to clean after a match, not to mention,the deposits will effect accuracy, even though we probably won't see a difference at the distances we shoot.