I think the format and subject matter are intertwined in a different way.
In my experience here a lot of members are either primarily artistic, or primarily engineers. Obviously a tremendous crossover though.
The whole right side/left side brain thing.
The artistic types are often more people types and use systems that allow them to shoot people easily.
The engineering types like the process, tinkering and working with larger formats and often hate photographing people.
So we get engineering types shooting quietly with a large format camera pointed at subjects that don't talk and move, and we get the artsy fartsy people persons shooting easily moveable cameras at subject that do move and talk.
And both types are here on APUG, which is very cool.