I know some dirt bike riders don't fit into this category, but can anyone explain to me why most dirt bikers need to rip the hell out of everything when they ride?

We get a lot of motos out along Ridgewell Rd (goes to hanging rock), and it's bad enough that they wreck the fire trails, but they are also getting around the National Park gate, and riding right up to the lookout. A few weeks ago I noticed that a log obstacle on the final bit of single track leading to the lookout had recently been chopped, and today I find a nice couple of donuts right at the lookout itself!