I was at that game. East side stands, so the Agroid Nation was down below me and to the right. What people who weren't there don't realize is that it took a significant amount of time before the goalpost ever ended up there, and it wasn't where the Gap Mob even wanted to go to begin with.
So it took some time for the goalpost to come down first of all. Then, the Gap Mob tried to take it out the SW ramp (the ramp the Tech football team uses), and the AD personnel and police blocked them from doing so, so the mob decides it would be best to take it out the NE corner, the corner the Agroid Nation was at.
The Agroids were done with their post-loss cheers, most of the stadium had cleared out because this was like 30 minutes after the game was over (maybe more), but when the Aggys saw the goalpost heading their way, they decided to stay and egg it on (in the videos you can see them waving their arms and saying "bring it"). So the Gap Mob did.
I just find the whole victimhood portrayal by the Agroids absurd and hilarious because they had to stand there and wait for quite a long time anticipating the delivery of the goalposts. They were as much to blame for the confrontation as anyone. But they love to play the victim.