Dude
Totally agree the gate was closed after the horse bolted. However, just practice trying to be nice when confronted by mindless morons. There are plenty around to get practice on. "Crowd control engineers", i.e. bouncers would be a good start.
As for those nice TSA guys, the ATO's if they are worth their salt, will assist greatly on readmission's. They have people employed just for that purpose as I'm sure you are aware. Customers should insist they give you all the help they can, or threaten to go elsewhere.