The garage in question
Apparently Chapman has a two car garage and a five car garage. The house is more than 10,000 square feet. It would be hard to characterize his girlfriend as feeling endangered when he goes to his garage a furlong away to let off steam.
Also, it is hard to charge a guy with felony vandalism for shooting up his garage when he is worth $30 million bucks. Plus, he lives in the gunshine state. Plus, his outside acreage may be large enough that he did discharge his gun in a safe direction. Plus lawyers can be baseball fans too. Maybe the local prosecutor and the police let him off with a warning.
Here's a more sensitive point: In states with elected prosecutors and elected sheriffs, the rich locals tend to get more free passes than the street level baddies. Maybe he should have been charged with shooting guns in a neighborhood, but wasn't because he is rich and prominent.