it's almost a necessity to have a big truck. Everyone, and I mean EVERYONE has a big truck. A half ton is the starter, it's the least you need to have. Most guys need a big diesel truck.
In area's where an office dweller is commuting with his big truck - in a lot of those cases they're serious weekend warriors. I have a lot of buddies who fit this bill. Hunting/hiking/camping almost every weekend, so the truck ends up being their everyday commuter by default.
I feel like the whole "Big truck is a sign a guy is compensating" has some merit, but is not true in the vast majority of cases. Are there tools who are insecure (for whatever reason) so they make up for it in tough guy trucks and shirts that look like tattoos? Sure. But they're not as common as the person claiming this stereotype is.