Welcome to Flyertalk.

Happens all the time that airline employees team up with the TSA to degrade passengers. You missed your flight (which was your fault, not that of the airline) and pissed off the airline employee in your attempts to get on another flight. Airline employee finally reacommodated you but got the last laugh.

Piece of advice: Delayed flights don't mean you can stroll to the gate after the original boarding time, like you did. Sometimes delayed flights aren't quite as delayed as the airline estimates they are.

So the bottom line is that you argued and complained about something for which you were at fault. Airline employee taught you a lesson.