The point is that in cases like this no TSA employee has to be compromised. These guys were using employee entrances and we all know that they receive almost no screening when going through the employee access points. It's not the drugs that I am concerned about but the demonstrated security flaw. If an employee can introduce drugs then they could also introduce other types of contraband, some of which could go boom.
Another factor, in a deal like this the employee only loads the contraband on the airplane. What do they care if the airplane blows up halfway across the country? Their skin isn't on the flight.
So stop focusing on the drug trade and look at the security weakness that TSA knows about and allows to continue.
I don't think TSA gives 2 cents about security and the abuse that passengers are put through by TSA is truly Security Theater.