stop using at&t
You don't necessarily have AT&T as an ISP to get this route. They own a lot of backbone and if your ISP can't get directly to that route, it may go through routers from multiple ISPs and T1 service providers to get there.

To note, this is an issue with BGP most likely. They just need to make sure you're not getting too bounced around. Normally it wouldn't be too bad if you're just loading a webpage, but in an online game like TF2, if the packet goes to Texas and back instead of a more direct route, it's going to cause latency.